Here's an idea: Participate in specialist forums/site and do some networking. You could learn a lot, teach other people and ultimately you gain quality backlinks.
This is a list with around 200 specialist social networking sites with PR from 8 and down, Alexa and Compete rank. The link opens a google spreadsheet. Didnt make it myself so i dont know how long it will stay there: http://bit.ly/d6o1Lz