If have personally tested the Oly T32 with my D80. Everything worked fine - exept that you don't get the TTL-control.
As a reliable third-party manfacturer I'd recommend Metz. Although as the interworking between the camera, the built-in flash and a slave-flash is quite intricate, I hesitated to use a third-party flash on my D80 and went for the original.
Thanks Thomas - now I know it is safe I can experiment with the T32. I have owned Metz before and will give them a look - I think TTL is the way to go.