You can get it at the Swedish tax offices called Skatteverket and you can find one at this address:
Monday, April 26, 2010
Getting your Personnummer
As you'll soon discover, once you arrive to Sweden you'll need to get your own personnumer. You'll need this number in order to open a bank account and to be able to work here. It's very easy to get and it will take you like an hour of your life and 1-3 weeks of wait after that until you receive it at your home address (here in Uppsala). Remember to take your passport with you when you go there!