What is the format for Xbox LIVE member profile URLs?

Previously, the format was http://live.xbox.com/member/[Gamertag], but this is no longer the case. For example, http://live.xbox.com/member/Xonatron no longer loads.How can I convert old format links to the current format?

EDIT: Also I am looking for the most elegant and clean URL possible, as shown from the previous URL that I used that removed the variable=value format.

Solution 1:

The format was changed to 'http://live.xbox.com/en-US/Profile?gamertag=[Gamertag]', where '[GamerTag]' is your personal and unique name.

So your example would now be: 'http://live.xbox.com/en-US/Profile?gamertag=Xonatron'.

Solution 2:

The new format is https://account.xbox.com/en-us/profile?gamertag=gamertag.

It still requires a login but after that the format works.