Wrenching on a bike isn't too hard. Having the right tools for the job and reading up on what you are going to do BEFORE tearing into something the first time will allow you to do pretty much everything. The specialty tools aren't too expensive and I just buy what I need for the job I plan to do. Over the course of a year and a half, I've put together a pretty good cycling tool kit. Park Tools web site is another good site for mechanical information.