tedster - 2:08 am on Nov 15, 2008 (gmt 0)

I thought this situation was worth a direct question to Matt Cutts, and since we're a PubCon, I had a chance to ask. He said you should make your best guess at how long you will need the reidrect. Anything more than a week or two and you should use a 301 - otherwise the 302 will complicate things for you.

If you do get the go-ahead to go back to the original domain, it's true that it will take a bit of time to sort things out when the 301 reverses direction - but it will still be better than a long-term 302.