I just upgraded to snow leopard. Before, I had everything running fine, but now when I start the server from the terminal I get:
=> Booting WEBrick
=>
I've done all this... the only thing that has worked for me is
sudo env ARCHFLAGS="-arch x86_64" gem install sqlite3-ruby
Note: I did have XCode installed from devloper.apple.com, not the CD. The CD install of XCode Tools did nothing to fix this problem for me.
If you don't have any XCode installed, you may need to get XCode 3 or 4 from http://developer.apple.com/xcode. You will need to sign up for an account. Presently, you may download XCode 3 for free without paying the $99 annual fee.