Which E6600 do you have? A Core 2 Duo E6600 or a Pentium Dual-Core E6600?
If it's the Core 2 Duo E6600, then it's of the earlier 65nm process. Most recent LGA775 motherboards should support that CPU out of the box.
On the other hand, if it's the Pentium Dual-Core E6600, then it uses the newer 45nm process (and as such, it is actually a Core 2 Duo E7600 minus 1MB of the E7600's 3MB of L2 cache). As such, you will need a newer BIOS version that supports the most recent of processors for that motherboard.
Also, note the difference in their stock clock speeds: The Core 2 Duo E6600 was rated at 2.4GHz while the Pentium Dual-Core E6600 is rated at 3.06GHz. Both processors use an FSB1066 front-side-bus speed.
I personally had experience with only two such boards, neither of which is in current production any longer. One of them has had issues with certain optical drives while the other does not allow for tweaking at all. Thus, I cannot really make any recommendations as to which motherboards to get. And keep in mind that the selection of LGA775 motherboards have been diminishing for a little while now, so if you must get a motherboard, get one within the next three months or so.