Definitely, definitely, definitely email researchers in your field of interest (especially if they are familiar with your undergrad program or one of your previous mentors). List-servs and online job searches won't typically have any postings right now for all of the positions that are going to open up in the next few months (and who has time to check each one every single day). If you write an honest and detailed letter about your interests and reasons for wanting some paid experience, the worst thing you could possibly hear is that they don't have anything available right now or that you may have to volunteer for a bit until something becomes available (and if you don't get a reply, is that someone you would really want to work with for a year or more?). Also, when you are applying to an advertisement, make sure you spend some serious time catering your resume to each posting, and always (always!!) include a cover letter.
I recently decided to go the aforementioned route in anticipation of the likelihood that I don't get off the waitlist in the next few weeks, and was gloriously rewarded with several responses and a job offer within 24 hours (I emailed ~12 top researchers in my field, and included my CV). I'm not saying this will be the case for everyone, but I feel like the response to my letter had more to do with the honest sentiment behind it than my credentials did.
Good luck to everyone that's in this boat!
Last edited by chuckdanger; 03-09-2012 at 11:36 PM.