Is it easy to change the bearings on these hubs? And how much for the parts to do it?

Fairly straight foward, just remember that one bearing is retained by a circlip (difficult to see when covered in dirty grease) & the spacers have to be replaced in the right order or else the wheel will go tight when you do the QR up.
Details here
Bearings probably a tenner from your local bearing supplier.

There’s a number on the bearings, can’t remember what it is off the top of my head, but have a look at yours and give your local bearing supplier that number.

And – top tip – if you can, take it apart it a bag, it’ll save you searching the garage floor for the pawl springs for half an hour after they’ve pinged out. Wish someone had told me that… 😀

Read and note

http://mountainbikerides.co.uk/fettling/3-wheels/5-hope-xc-rear-hub-service.html

Top tip – an old rotor bolt will fit nicely in the end of the axle and provides somehting you can **** with a hammer without damaging the axel. you will have to hit it a *LOT* harder thank you think to get it to move,

sorry, didnt spot that someone had posted the link. shows how usefult it is though!

if not mentioned in the links, they’re 6001 2RS bearings, 4 of them.

Did my rear bearings a couple of months ago, with help from this vid:

[video]http://www.youtube.com/watch?v=_xm6RUYDyyo&feature=related[/video]

I did put the new bearings in the freezer as well, which helped getting them back in.