I can sort of relate since I'm in the same boat with my startup. The key for me was to set some goals for each week, tell my friends about them (to help keep me honest) and then to simply get cracking. Beyond that, I'd suggest that keeping focused can be as simple as calling yourself out for BS'ing. :)

As for part-time UI work, drop me a line -- I may have some stuff for you: paul.singh [at] philtro.com