travel center (central railway station) is found here.
To Uppsala from Arlanda airport:
Arlanda airport (code ARN) is about 30 km from Uppsala. The most convenient way to come to Uppsala is to take bus number 801 (bus stop number 13 at the exit of the terminal) or a train. The train leaves from SkyCity (between terminals 4 and 5).
Bus 801 Arlanda airport->Uppsala central station: every half hour, at 12 and 42 minutes past the hour. This is from Terminal 5, the starting point. Add 2 minutes if you arrive to terminal 4, and 4 minutes for terminals 2 and 3. It takes 45 min and the last bus leaves 03:12 (timetable valid to 2013-06-16). The ticket costs 100 SEK and can be bought from the driver using credit card.
Train Arlanda airport->Uppsala central station: every half hour at 16 and 46 minutes past the hour. It takes 20 mins and the last train leaves at 00:46 (timetable valid to 2013-12-14) . It costs 165 SEK and tickets are bought in the counter or in the vending machines in the lobby, before going down to the piers.
NOTE: Do not follow the Arlanda Express signs. These are for the express train to Stockholm only.
To Uppsala from other airports:
Some of the so-called low-cost air companies coming to Stockholm fly to the smaller regional airports of Skavsta or Västerås.
Note that these airports are not so close to Uppsala and they are not well connected, so getting to Uppsala can be costly and take a long time.