It's not massively different, (@ key at shift 2, " above the right hand shift). You can remap the keys if you want, but it's never bothered me.
Mark.
Actually I find the UK vs US (including international English?) keyboards quite different.
See
http://www.flickr.com/photos/neilchristie/156439321/ for flickr photos of UK top and US in the comments.
Things of note:
1. Differently shaped return key. UK: Inverted L type shape. US: rectangular
2. Left-Shift. UK:small US: large
3. Placement of ~. UK: left of Z, US left of 1 (this is normal)
4. Placement of \. UK: left of return. US: above return
5. UK: shift-3 £, option-3 US: reverse?
6. UK: option-2 . US: same?
7. UK: icons for shift, tab, caps, return, delete, enter. US: words instead
I use to have a powerbook with intl english keyboard (i.e., US) and now I'm on a UK macbook. I found that the first four changes took awhile to get use to.