[kmak]

http://train.usaco.org/usacogate

It walks you through the algorithms, though you need one of the languages.

There's some terse list at

http://www.algorithmist.com/

that might help. (Disclosure: I started Algorithmist)

[ianbishop]

I would just like to say thanks! Without the Algorithmist, I would have pulled my hair out more than once.

[kmak]

Thank the contributors, I only maintain the site! ;) Of course you can thank the site by paying it forward!

That said, UVa's problems are better defined nowadays. Tough problems are actually tough, instead of trying to trick people!