What's your budget? You should spend very little for such an old CPU.
You can verify if a motherboard supports the Intel Pentium 4 3.4GHz Extreme Edition at http://www.cpu-upgrade.com. Then double-check the manufacturer's site.
Here are a few compatible and inexpensive motherboards on eBay.com:
Asus P4P800S
Asus P4P800-X
Asus P4C800-E Deluxe