I have a pentium D 820. My motherboard just went to the pooper a few days ago. If I buy the Gigabyte DS3 conroe motherboard, can I slap this cpu in and use it?
How soon before you upgrade to a Conroe CPU? If you're not going to do it in the next couple weeks, I'd wait and see what the new revision of the DS3 looks like. I can't imagine it'll OC that much different, but I believe it's on the same PCB as the DS4/DQ6 and has 2 x16 slots.
If you need a board right away, I'd see what newegg (or your local favorite e-tailer) has by way of mATX boards that support the P-D 820 you have. You could then swap the CPU/motherboard combo into a HTPC or have a nice, small, secondary box for whatever you need it for later (or just sell the combo).
I only suggest that because that's what I did, and I have a P-D 805 and ECS Xpress 200 board as a backup to my Conroe setup. It's great for when I'm fooling around with stuff and I don't get it done. I always have a computer to use.