Making a hobby a job - Talking with Eric Herbrandson about his Silverlight-based MicroISV

Eric Herbrandson has been working on the site creating a Silverlight-based audio mixer at night and weekends. What's the best way to hold down a full time job while pursuing your passion? Was it hard for Eric to learn a new technology and apply it to his little ISV? And some tech chat about his product, AudioOrchard (now ScratchAudio), what was possible and what wasn't.