CSS is really just a layout skill and it only gets difficult depending on how far you're willing to take it. See
http://www.csszengarden.com/ to see how simple style sheet changes can change the look and feel on a site. If it's a buddy site sort of site it's most probably the working parts of the site the programming that will be the real head ache. I can design but I'm not a programmer and that I know that is often the tough bit, the working elements and user interactivity. Maybe flashwiz might be able to give you a few ideas he has a great mix of design and coding skills. I'm quite happy to give ideas on the layout though.