Other than that, I'd also check the community mailing lists, the ruby-nyc list for example gets a lot of job postings! Another Rails specific place I've had interest from is workingwithrails - lots of people go through profiles there and send out emails.
Thanks for the mention of Standout Jobs, I appreciate it. Startup jobs isn't our focus necessarily, but we do have a lot of great startup companies using the product. And we're not a startup job board; we'd much prefer to turn every startup's career site into its own destination site.
The best way to get a startup job is to network into it. If you're in SF, this is very easy - just go to all the web2.0 parties/meetups and you'll meet people hiring in no time.
Thanks noodle! I run nPost (http://www.npost.com) and definitely appreciate the good feedback.
There are lots of job boards out there, but only a few that are solely focused on the tech startup community, such as nPost and Startuply. Both only make the community stronger.
Startuply has a great site and we wish them the best.