Forks

Can someone point me in the right direction on how to measure my frame for buying new forks?

Are you asking about the width of the steerer tube or the length of the fork? do you have a bike that you're already comfortable with to compare the length or is this your first build? did the bike you're working on already have forks that you're replacing?

the length isn't too much of a problem as you will need to measure the length of the headtube and add how much fork you want sticking out of the top. go longer as you can always cut back a steerer but not add to it (that is, of course, dependent on whether you're going unthreaded or threaded). as for the width, you'll either want 1" or 1 1/8", but that will depend on the headset that you've got on the bike.

You will need to know whether you need a treaded fork or threadless ( this is determined by the headset)
You will need to know what width steerer you want ( usually 1 inch or 1 1/8 inch)
You will need to know what length of steerer you want (length of head tube, headset and how many spacers you want, so you can tweak you handle bar height)
You will need to know what type of fork you want in terms of wheel size for rim brake mounts( 700cc, 650cc, 26inch etc),
You will need to know what length of fork you want (which is measured in axle to crown length, this is based on the frame geo)
And then there are other thing to take into considerations like whether or not you want mounts for a rack, mud guards, tyre clearance etc

Think ive covered most of it

Right thanks for yoour help lads, I have measured width of the steerer which is 1 1/8.
I have measured the length of the steerer 24cm. I am not too sure on how muchI should have coming out at the top. At the moment it is perfect.
How can I tell if it is threaded or not?
There is a picture here if you think you can tell from looking at it http://www.lfgss.com/picture.php?albumid=1490&pictureid=9795

threadless 1 1/8, buy forks and chop them down depending on how many spacers you want, if any.

threaded

threadless (ahead)

also that pic says nothing, yes it has a threadless stem, but some bikes come with thread to threadless converters like this from sjsc

Sheldon brown is your friend :)
http://www.sheldonbrown.com/headsets.html

Very useful..thanks mate. I need forks that will fit 650c wheels....If anyone has any 650c, 11/8, threadless let me know.

Woolley