Bottom Brackets

I need to get a new bottom bracket for my road bike and don't know what size to get... the only markings on it are BC1.37.24 on one side and RC1.37.24 on t'other. Any ideas?

Also, how hard are they to fit? Have never done it myself, and am pretty strapped for time due to study, but also want to learn for the future (and save £20-odd quid getting someone else to do it)...

Cheers!

jim,
forgive the patronising comment - my intention is to help. you seem pretty clueless, first, how do you know you need a new BB?

The cranks are wobbly so to speak... They move towards and away from the frame ad I pedal

cranks are more likely to be loose than the BB broken tbh.
can i suggest as follows:

1) determine what crank / BB coupling you have (e.g. splined; square taper; external cups)
2) establish what tools needed to remove cranks
3) remove cranks and inspect BB. if the BB is moving around as it shouldn't then you are probably right, it's fucked, unless it's an old style loose bearing one in which case could be serviceable. if problem is flappy cranks unlikely to be BB issues imo
4) if BB is fucked establish what tools you need to extract and replace...
5) if BB ok then replace cranks nice and tight - for flappy cranks check that they are not damaged, particularly if using square taper BB

sheldon brown is your friend. also, bikemanforyou on youtube has helpful videos, particularly for servicing older bike parts. he's a bit, well, you probably wont want to like him but he knows his shit.

ok, thanks. will have a tinker...