The US Mint's website hasn't posted these yet (www.usmint.gov) - BUT I have been able to find the officially approved designs for the 2004 quarters online (Michigan, Florida, Texas, Iowa, Wisconsin, in that order).

Rather than copy the JPEGs, the legality of which might be questionable, I'll just post the URLs, which I got via Google.

http://www.statequarters.com/Coinag...ns/Michigan.asp
http://www.statequarters.com/CoinageDesigns/Florida.asp
http://www.statequarters.com/CoinageDesigns/Texas.asp
http://www.statequarters.com/CoinageDesigns/Iowa.asp
http://www.statequarters.com/Coinag...s/Wisconsin.asp

The Michigan quarter will be released on January 26th, their statehood anniversary.
The others will likely be released in 6-8 week intervals following that, through the end of 2004.