one letter URLs?

As my one day of blogging for the year is about to come to an end, I feel like I should mention my recent fascination with one-letter URLs. Did everyone already know about this except me?

In case you don't already know: it appears that certain (very large) websites have somehow purchased the right to have one-letter shortcuts to their sites. So if you just type "w" into your browser box and hit enter, you go to The White House's website.

Some other interesting ones:

a: apple's site. duh.

b: the israeli informaton center for human rights in the occupied territories. whoa.

e: E! Online. i guess i should've seen that coming.

m: whoa! not microsoft! actually, it's the website for Texas A&M University. why?

l: your portal to the Council of Europe. que majestique!

etc., etc.

Can anyone tell me how this works? What process must you go through to get one of these? How much does it cost? I'm really curious, but I have to leave work now and I can't search around and find the answer for myself.

Clue me in, nerds.