Yep, already google'd that link up... found a few more, too, and looking into it.
CPU-Z Reports default voltage at 1.15v (0.0000 in BIOS), and increasing it to 0.0250 in BIOS puts the voltage at 1.176v. I've increased it a bit since then, and also the FSB, though it seems like the actual Core Voltage takes a leap when you increase it past 0.0250 in BIOS - I increased the BIOS cvolt to 0.0500, and now the core voltage is at 1.33v
(max rated voltage for my CPU is 1.35v)
I'm currently testing for stability at 2700MHz, with 1.33v and FSB 300MHz (1200 in BIOS) though I'm sure I can go further than that.
I found this thread earlier, but it doesn't list my batch:
The Official Core 2 OverClocking Database *READ 1st Post for Instructions* - [H]ard|Forum
My CPU batch is L709 A441. I know people with batch L709 A442 have had some impressive overclocks:
XtremeSystems Forums - View Single Post - Conroe Overclock Database
Of course the 4GHz overclock can be ruled out, since I don't have phase cooling... XtremeSystems Forums - View Single Post - New E6600 batches, post your Overclock