Pins are limited to 3000 of each (still to be confirmed).
Click here for the official website page
As an example (and because I live in LB Sutton), here's my 'home' pin
Image reproduced from www.london2012.com
Notice that the names of the boroughs are not written in the 'brand font'. Most of the previous pins that have had writing on used that font - look at the London at Night set. It's not always the case, the 1000DTG pins used a mixture of fonts, but it's interesting that these pins use a 'regular' typeface for the names.
The press release sites all the usual retailers, so hopefully they'll be available in the next week or so.