I'm not all that experienced with overclocking, but I do know a few things that will ensure a system's stability:
1. Keep the HTT bus speed near 1GHz, and certainly below 1100 MHz. So if you up the LDT bus to 220 MHz with the stock 5x HTT:LDT multiplier, you'll get a 1100 MHz HTT bus speed. Drop the HTT mult. to 4x and give yourself an 880 MHz HTT bus speed. It doesn't affect performance one bit and leads to better stability.
2. Unless you have RAM that's either rated above DDR 400 or has tight timings at DDR 400 (something like 2-2-2), don't overclock the memory bus more than, oh, 15-20% or you'll cause the system to be unstable. If you want a high LDT bus to OC your chip with, select the "DDR 333" setting on your board and then OC from there. That simply sets in a 200:166 memory divider and will let you get an LDT of 241 with the RAM running at its rated 200 MHz DDR 400 speeds.
3. If your RAM is rated at DDR 433 or better, you might need to loosen up the timings and command rate to get it to be stable when overclocked. Memtest86+ is your friend to test memory stability. If it can complete a half a dozen cycles with no errors, you're more than golden.
4. Don't increase the Vcore. If you don't overvolt the CPU, you are far, far, less likely to roach it by going too far. Keep it at the stock 1.35V and watch the temps. If the temps are fine, you really can't cause very much if any damage by overclocking*
5. Don't let the full-load temps get beyond the mid-50s and you'll be fine.
*Or so I am told. It certainly sounds reasonable as higher Vcore can lead to electromigration of metal ions, and that should not happen at its rated Vcore, even if the LDT bus and clock speeds are bumped up. But anyway, be careful and smart and you should do fine.