If you're just looking to search for modules by category CPAN already lets you do that easily. You can also view modules by author, name, and recentness.

Picking amoung the various modules is the hard part. For common purposes everyone seems to have their favorite, but there usually are 3 or 4 main ones that people use. Ask around, then try all of the commonly recommended (and maybe some of the not so commonly recommended) ones out and use the one that best suits what you're trying to do.