If I am recalling correctly, the Samsung Vibrant and Samsung EPIC 4G are thus far the only US Galaxy S phones to receive their update to Android 2.2. The Samsung Captivate has had its fair share of hopeful moments, too, such as an update page that went live but was quickly pulled after word got around. Now a new leaked build of Froyo for the Captivate might signal the the update is just around the corner for Galaxy S owners on AT&T.
This build is numbered as I897UCKB1, but we will call it KB1 for short. If you are into taking risks and rooting, the ROM is available for installation right now over at XDA.