Request Tracker is actively developed and very robust http://www.bestpractical.com/rt/

I followed George Ou's guide and built a great NAS for real cheap. I upgraded a few components and ended up spending $500 for the parts then I spent another $500 on five 500gb drives to setup a RAID 5. Of course you could spend a lot less, its getting cheap to build your own system these days. Here's the article for reference Build the $340 NAS for half the price but double the speed