Most developers tend to think that QA is for button pressers and failed programmers. However, having a couple of good programmers on the QA team can dramatically improve a product. If you're really a good programmer then you can take requirements and write GOOD tests. Also, as a programmer, you can deconstruct what the dev team has built, and look for ways to make it fail (i.e. the cases they failed to consider). If you understand the nuances of the language, you can better anticipate the edge cases that a lot of non-technical QA folks would miss.
I've been down this path, and found that when a dev team knows there's someone who will call bullshit on their submissions (and can back it up), the code that's checked in tends to be better.