RSA/DSA questions

(I'll admit it, I'm a crypto weenie. I know enough to spell RSA and DSA correctly, and that's about it.) Does anyone have any pointers to informative papers (especially analyses and critiques) to RSA and DSA in particular, and in general, signature algorithms? The only page I've found is in the RSA Labs FAQ, and (obviously) digs into DSA. A co-worker is generating some SSH keys, and it's been some time since I actually looked into either algorithm. PuTTY recommends you avoid DSA, which was a bit of a surprise to me, and prompted this thus-far fruitless search for comparisons/critiques.