With American schools spending billions of dollars a year buying textbooks, a Brooklyn-based company is offering a new Web site that gives kindergarten teachers full lesson plans — at no charge.

The site, which is called Free-Reading. net, works like the online encyclopedia Wikipedia. Teachers can sort through hundreds of lesson plans, searching through subjects that include “Letter Sounds” and “Word-Form Recognition.” After registering, they can add their own lessons.

The site adds to several efforts around the country to make curricula more widely available through the Internet. Yale University recently made some of its most popular classes available to audit online for free, and another Web site, Curriki.org, is trying to collect a Web site full of free lesson plans for elementary, middle, and high school students in subjects from math to foreign languages.

But the ambitions of Free-Reading’s creators, two Rhodes scholars at a company called Wireless Generation, based in the DUMBO neighborhood of Brooklyn, make it unique. Larry Berger and Gregory Gunn aim not just to connect reading teachers, but to slash at the heart of a business so formidable in American school spending that Mr. Berger has dubbed it “Big Edu.”

“I wouldn’t say that this is the death of the textbook,” a vice president at Wireless Generation, Andrea Reibel, said. “But this may herald a big change in how high-quality instructional programs are created, distributed, and priced.” The idea is that by freeing school districts from all the money they now spend on textbooks, Free-Reading can spark a revolution in how schools serve children, directing resources away from the textbook ideas that have been around for hundreds of years in favor of products now in fashion as the crucial tools for reviving American education. (Not coincidentally, many of these tools — testing and data systems that help teachers customize their instruction to individual children, and on-the-job instruction that teaches them how to do that — are now sold by Wireless Generation.)

So far, Free-Reading’s reach is limited. It is not a full literacy curriculum, just a set of “intervention” activities for supplementary use, and it targets only very early readers. But Ms. Reibel said that since its November release, Free-Reading has spread quickly. The site has had 77,000 unique visitors since the summer, 4,400 of them from New York City. Major school districts, including the Boston Public Schools, are testing the site, she said, and the state of Florida may soon add it to a list of approved supplementary reading curricula.

“It’s kind of like Wikipedia,” a teacher at the Achievement First elementary charter school in Bushwick, Brooklyn, who uses Free-Reading, Dixon Deutsch, said. “Early on, people thought Wikipedia was just another Web site, but now look at it.”

The site is popular in Mr. Deutsch’s classroom, where struggling students — the school calls them “scholars” — come to get their reading skills spruced up.

“I’m so happy to play Bingo!” a kindergartner named Tyrell squealed, as Mr. Deutsch began a recent lesson he downloaded from Free-Reading. In the game, students use letters to fill out a Bingo board, and instead of calling out the letters, the teacher displays them, forcing students to sound them out themselves.

Tyrell wasn’t the only one having a good time. Before any letters had been called, students were already shouting “Bingo,” prompting Mr. Deutsch to deliver a mini-lecture reminding them of what the word is supposed to mean.

The teacher said that before Free-Reading, his school’s repertoire of lessons to add to basic drills was limited. Some teachers would vary the volumes of their voices when saying word sounds out loud. Mr. Deutsch sometimes would play the commercial word game Boggle.

Free-Reading, whose lessons are monitored by an advisory board that includes several education professors and literacy experts, has changed that.

However, it has not yet saved Achievement First much money, if any. Though the charter school network now pays about $37,000 a year per school for its basic reading curriculum, SRA, it does not pay for a Free-Reading equivalent, Achievement First’s director of external relations, Lesley Esters Redwine, said.

Though Ms. Reibel said Wireless Generation could well get into that market, too, Ms. Redwine said Achievement First is not looking to replace SRA, either, citing top-notch results.

Assuming the promise holds, Free-Reading could help the school save in other areas.

After Mr. Deutsch finished his kindergarten lesson, he began talking about his second-graders, who needed help with word comprehension and complex vocabulary. Those are areas Free-Reading does not yet target. So Mr. Deutsch typed SRA’s Web address into his Internet browser.

The site had a set of tools. But they had a price tag: For a few months worth of lessons, the cost would be $381.66.