Yes - The main overclocking tool you have is increasing your FSB. Now, a 1.86 to 3Ghz is a pretty steep overclock - With a 7 multi, you'd need to run your FSB at 430Mhz: That's going from 1066 to 1720Mhz. You can do that, but at that large a jump you'd:
(1) Certainly have to bump the voltage to your CPU some - More volts = more heat. Is your cooling up to the job?
(2) Likely have to bump chipset voltages as well: 266 to 430 is a pretty healthy jump. My board is going 400 on Auto, but I'm pretty sure that's about as much as it'd go without bumping the chipset some. Again: More volts = more heat, and do you have good cooling?
(3) Nearly all Intel boards link memory and FSB speeds. You'll have to watch out you don't clock your memory too hard by accident. Not too big a deal, but you'll have to pay attention. At a 430 FSB, you could mildly overclock DDR2-800 RAM at 1:1 and end up with an 860 clock there. Should be fine given any decent DDR2-800 RAM.
By way of (vague) comparison: I have my Q sitting on an 8 multi/400Mhz FSB with my memory running at 800. Runs very nicely, CPU is fine, chipset a bit warmer, at basically stock voltages. A similar setup would have your chip running at 2.8Ghz, presuming you leave the multi at 7. I don't know where you are now, but I'd pick an intermediate step before jumping to 400, for sure...
By way of disclaimer: My Mobo/chipset/proc/memory are all different from yours. Therefore your mileage *will* vary.