What tools do I need to replace my bottom bracket?
As this is an older octalink crankset/BB you will require a:


Crank Extractor like this to remove the cranks.
Bottom Bracket tool like this to remove the bottom bracket.
Dust cap removal tool (if it has these) like this
8 or 10mm hex wrench for crank bolts.


This is likely to require a lot of effort to free up after 12 years so I'd recommend a repair stand.

For fitting a new 10 speed crankset (at Deore, SLX, XT etc level) it's likely you'll need to move to a threaded external bearing BB such as Shimano BB70 which will probably come with the crank set you purchase. This requires:


External bottom bearing tool like this to install the bottom bracket and no other tools.


I was on the Park Tools site so used their tools as examples, many brands make similar tools. They also have a good reference section to learn how to work on a bike here.

Personally I would recommend trying to borrow the tools to remove the BB from your LBS rather than purchasing new as the standard for mountain bikes has changed to (many different) external bearings systems. It may end up you purchase them for this job and never use again....