I just done this properly:)
To do it :
First make sure you are logged on with your Xbox live account - you don't have to have gold - I only have silver and this worked fine.
I then created my profile in Your Shape - so I think thats one the main menu and then set the needed stuff up (age, weight etc).
Then I went to U-Play - you can do that by pressing x on the control pad. You will need to use the pad for entering passwords and things.
When on Uplay - it links your Xbox account to a new uplay account - I think you can link to an existing uplay one but I didn't bother.
You will receive an email to the mail address you registered your xbox account with once you've gone through that step.
And thats about it.
From then you can go to web on PC and access the yourshape center. Note that here I had a few problems in that the site thought I was French (even though I'm in NL) - work with it - you will be able to work out which links to press if this happens. Then you can set up the rest of what you want to do in English - it sort of works out what you want when you complete your profile.
You can also then set yourself games and challenges for others if you know their gamer tags (xbox accounts) etc.
Your mileage may very with the above but it's certainly not un-doable:) (unlike some of the YS exercises;) )
| current weight: 222.0