Back in August of 2010, T-Mobile sent out an end of life letter to stores and recently, the Android 1.6 (Donut) source code for the Behold was released by Samsung. For those of you still holding onto the spirit that was the Behold, you now have some reprieve with a custom ROM based off Android 2.2.1 (Froyo).
The website EB-Productions has a release of this custom ROM. It shows that the ROM is far from complete, but getting the Behold to boot up with the ROM is one step closer to rebirth. Hopefully you can check out a more complete ROM with all the odds and ends soon.  Until then, check it out if you are so inclined.  Root required.
Source: Android Central