I'm in a similar position. I'm currently a full time designer for an agency but have deciding that it's time to go freelance. Due to various issues at work, I hope to leave as soon as I am able and plan to work really hard to gain jobs while working through my notice, although I do have some leads already.

Reading the threads I now know that I need to register myself self-employed and that if I want to form a limited company, I can do that further down the line. I'd like to keep things a simple as possible for now.

I'm trying to decide whether to work under my own name or under a general name (i.e. X Graphic Design) that makes me look more professional. If I go with the latter, do I need to register it, etc?

After reading comments here in the forums, I feel much more positive about making the jump in to Freelance Design.