Moor cool codes
I'm using a Dell Streak US version 1.6 build 6601 and they work on my phone.
Check out this code. * # * # 4 6 3 6 # * # *
I can't post the web site, but if you message me I'll be glad to pass it on.
Im sure this info is here some where on XDA, but this looks like a good place to have it.
BTW this code was for version 2.1, but worked well on 1.6