Belly up to the trough, everyone – the free-agent feeding frenzy has begun.

For the second year in a row, too many NBA teams with money to spend are chasing too few stars. Teams such as the Bucks, Cavaliers, Hawks, Clippers, and Sonics have a war chest of money to spend because they’re so far under the cap. But only a few free agents are really worth the money, and most of them will choose to stay with their current teams. The result, much like last season, should be some outrageous deals for a few lucky souls whose contracts expired this year.

Pieces are already moving on the chessboard with Ray Allen’s decision Monday to stay with Seattle for a reported five years and $85 million. That leaves just a handful of top-tier free agents – Milwaukee’s Michael Redd, Washington’s Larry Hughes, and Phoenix’s Joe Johnson – and all three seem likely to stay put.

Meanwhile, the cash-strapped Knicks and Nets will be fighting over lesser scraps this off-season. Both clubs are over the salary cap, so the maximum contract they can offer is the midlevel exception, which starts at about $5 million a year.

That hasn’t stopped them from trying to hook some big fish. Nets coach Lawrence Frank paid a visit to Portland’s Shareef Abdur-Rahim on the first day of free agency in an attempt to lure the high-scoring forward to the swamp. Frank and Abdur-Rahim share a history from when both were in Vancouver, and the league’s best hyphenated player since Kareem would certainly be a bargain acquisition at the midlevel price. New Jersey will have to wait for an answer, though. Abdur-Rahim is expected to explore sign-and-trade possibilities that could compensate him more handsomely than would a midlevel contract.

While the Nets seem primarily focused on one player, the Knicks are targeting several. Isiah Thomas is making a push to add both Boston’s Antoine Walker and Washington’s Kwame Brown, although the logic here is in short supply. Walker and Brown both play power forward, and that spot on the roster is already more crowded than the L.I.E. on a summer weekend. The Knicks have Malik Rose, Michael Sweetney, Maurice Taylor, and Jerome Williams at the position, plus the 6-foot-10-inch Tim Thomas at small forward, so it’s unclear why the organization would want to go seven deep at the position while its other needs are so glaring.

Isiah has long had an affinity for Walker, a fellow Chicagoan. Thomas reportedly is willing to offer the Knicks’ full mid-level exception to get the shot-happy forward, rather than targeting more pressing needs like center or small forward. That would be a missed opportunity for New York: A wing player like the Clippers’ Bobby Simmons or a shot-blocker like Milwaukee’s Dan Gadzuric would be a much more intelligent use of the money.

As for Brown, you might want to sit down before you read this. The Knicks supposedly want to give Sweetney to the Wizards so they can do a sign-and-trade for Brown. This is rumor, not fact, so we should give Isiah the benefit of the doubt. But if he does pull the trigger on such a ridiculous trade, James Dolan should find the pinkest slip in his possession and slide it under Isiah’s door, taking care to cut the phone line before Thomas can execute any more deals.

Sweetney averaged 17.2 points and 11.1 rebounds per 40 minutes last year and led the Knicks with a 53.1% shooting mark. Brown, meanwhile, slumbered through the year with 12.9 points and 9.1 rebounds per-40 minutes, and was kicked off the team in the playoffs because of his lackadaisical attitude. Sound like a fair swap? And while some still gush over Brown’s potential, keep in mind that Sweetney is actually seven months younger.

Perhaps more surprising, if less baffling, is that Thomas is said to be contemplating trading Stephon Marbury. Granted, the success generated by Marbury’s departure in New Jersey and Phoenix provides a strong incentive, but Marbury’s contract is a major deterrent – he still has four years left at the max. How ironic it would be for Thomas to undo a move that was originally the centerpiece of his plan to rebuild the Knicks.

Of course, that rebuilding plan may gain steam depending on the availability of New York’s most coveted free agent: Larry Brown. Isiah is said to want Brown desperately if he and the Pistons should part ways this summer, which is why Thomas has been keeping Herb Williams twisting in the wind for so long. Unfortunately, Brown and the Pistons had another inconclusive meeting yesterday, so his status remains uncertain.

The problem, of course, is that Brown is a veteran-friendly coach who rarely finds minutes for young players – if you don’t believe me, just ask Darko Milicic. That means that Thomas’s first-round pick, Channing Frye, probably wouldn’t see many minutes, nor would players like Sweetney or, if acquired, Kwame Brown. Jamal Crawford and Walker, with their horrendous shot selection, also would seem to be poor fits for Brown’s system, as would a shoot-first point guard like Marbury. Thus, Isiah would have to consider a complete makeover of the team just so it could fit his coach of choice.

With or without Larry Brown, the Knicks’ attempted maneuvers this week are jarring and disappointing when one considers how well the summer began. First they nabbed their preferred big man in the draft by selecting Frye. Then they filled a need on the wings in the trade of Kurt Thomas for Quentin Richardson, and got a player who was 10 years younger in the process. Even better, the Knicks also got a first-round pick – ex-Washington point guard Nate Robinson – to back up Marbury.

But Sweetney for Brown? Adding Antoine Walker? These aren’t the kind of moves that a team serious about rebuilding should even be considering. One wonders if Isiah won’t again short-circuit the process in a grab for immediate gratification, much as he did with the acquisitions of Marbury and Tim Thomas two years ago.

If so, Knicks fans need only gaze longingly across the river to see how an organization can rebuild quickly without spending extravagantly. While the Nets are maneuvering to add another inexpensive, productive piece in Abdur-Rahim, the Knicks only seem to be building a path toward a permanent seat at the draft lottery.