boy, kanbeki... sorry you're havingtrouble getting good answers to your question... but here's what i have to offer...
but an athlon xp 2500+, abit nf7-s...
just kidding!
first thing i'd do... since you have pc2100 memory (133mhz), set your fsb/memory ratio to 1:1 so your memory will be running at 100mhz. so as you increase your fsb, your memory will go up with it and you won't be limited by the memory running over it's 133mhz rated speed. you copy? like, if you get the fsb to 115, the memory will be running at 115 (230 ddr) and still within spec. and honestly, having your memory running synchronously (1:1) with your fsb is the most efficient and usually the best way to go anyway.
then do like you were doing. try 110 right off the bat and i bet it will be stable. but do 5-10 minutes of stress-testing in the form of a 3d benchmark or game. if everything seems good, then go back and up it another 2mhz and do another round of testing. and just keep doing this until you encounter problems. at which point, lower your fsb 1mhz and see if it's fine then. if not, lower it another 1mhz. once you find your limit, you can if you want, increase your cpu's voltage. this will likely enable you to achieve a higher overclock so after you increase it, go back to finding your max fsb again.
but watch your temps! increasing the frquency and voltage both directly affect your cpu's heat output. but also realize that as long you as you don't make any large increases to frequency and voltage, it's very unlikely that you'll cause any damage to your processor. so don't be afraid.
hope this is clear. good luck and let us know of your progress.