New CPU Installtion, How easy?

What model laptop is it? Some are easier than others, but chances are you will have to disassemble a good portion of it.

It is an Acer Travelmate 4062LCi.

The best you can upgrade to is a Core Duo T2250 (1.73 GHz) or a Core Solo T1350 (1.86 GHz). You would really only notice a difference in gaming or video or sound editing. IMO it is probably not worth it.

Im not asking whether its worth it, I just want more out of my laptop, multi-tasking is a hassle, and I wanted to know whether anyone had any experience in replacing one?

It will probably not be too hard. You will most likely have to remove all the bottom panels and remove the hard disk to take off the main bottom panel, and then once that is off, access to the CPU should be fairly easy. If you are having trouble multitasking, increasing your RAM to 1 GB will help a lot.

Im thinking of upping my RAM, ive found the exact RAM I need but its a little pricy.

If you have one 512 MB stick, then another should cost $50 - $60, and two 512 MB sticks should cost about $100 - $120 depending on whether it is value or high end RAM.

Here is some inexpensive RAM that is compatible:
http://www.newegg.com/Product/Product.asp?Item=N82E16820231038

Here is some higher end RAM:
http://www.newegg.com/Product/Product.asp?Item=N82E16820227106
http://www.newegg.com/Product/Product.asp?Item=N82E16820220126

Anywhere that ships to UK?

This place does.
Mainstream:
http://www.aria.co.uk/ProductInfoComm.asp?ID=24349
Higher end:
http://www.aria.co.uk/ProductInfoComm.asp?ID=24225

Thanks ill check it out.