I'm thinking about doing this myself and my husband and I were talking it out this weekend. We'll do the work ourselves and order the parts off the internet. Yes, you'll need a new bottom bracket, the new compact crankset and that might be it. Depending on your front deraileur, you may not need to replace it (though, based on your shifting issues, you might want to!) and your chain, rear deraileur and shifters should all work fine with the compact.

On an aside note, I LOVED my triple and never had one ounce of shifting trouble with it. I'm nervous that I won't like the way the compact shifts and that I'll really miss all those in-between gears!