Yep, as you can see, this is pretty addictive stuff. Once you get the hang of it, you just can't stop yourself seeing how the next colour is going to work out. I think the fact that I'm using aran wool has been a great help for my first Fair Isle project - you can clearly see where you are and there's less stitches to worry about.
The tricky bit is the weaving in of the wool as you go along. If a colour is not being used much in a particular line, then you have to keep catching it in with your working colour, so as not to leave a big loop at the back of the work. This can get a bit tricky when you're using 3 different colours! At the moment, I end up with a great bit tangle of wool at the end of each line, which I then have to untangle before I can carry on. I guess there must be a technique for dealing with this, but I have yet to figure it out.
Despite the fact that I'm loving the actual knitting, the whole cardigan has been slightly tainted by the fact that, when I proudly showed it off to husband last night, he said 'oh, a Christmas jumper'. Eeeuch.
Hope they like it :-)