Matthew, I've tried to send you a reply to your PM, but for some reason it's still in my outbox here - in case there's a problem with it, here is what it says:
Well you must be bloody strong to get the drive side off without a tool, but you were wise not to try to force the other one. You need a crank puller like this one (you could maybe get a cheaper one than Shimano, but this is what it looks like) plus a 16mm spanner
http://www.chainreactioncycles.com/Mode ... odelID=671
then after that you need a BB removal tool like this plus a 32mm spanner (but I use an adjustable one)
http://www.chainreactioncycles.com/Mode ... odelID=689
you start with the non drive side of the BB. You may well find you need to lock the tool onto the BB by screwing the crank bolt through it with a suitable large washer (e.g., the one I use is 32mm across and has a 9mm hole) You may need to use quite a bit of strength, but it doesn't sound like that's a problem. The non drive side comes off in the normal way, anti-clockwise, but always remember that the drive side of the BB has the opposite thread, so it comes off clockwise
To install the new BB, just repeat the process with the BB tool, starting with the drive side. You won't need the crank puller to reinstal the crank arms, just tighten the bolts (I use a spare handlebar over the Allen key for a bit of extra torque)
if you don't want to buy the tools, ask your friend - but always remember that the first rule of bike maintenance is 'Never lend your tools to anyone, not anyone, not ever, no'. So don't be offended if he won't lend them to you - you need to take your bike to his place and do the work there. Only mad people lend out their tools.
get back to me if you hit any snags
cheers
Anthony Young