When it says 'cleared' on the map, does it actually mean they don't respawn, like in Oblivion?

If they do respawn, how long does it take for them to do so?

According to the UESP Wiki, they respawn every 10-30 days. Not sure about the loot.

Here:

http://www.uesp.net/wiki/Skyrim:Places

http://www.uesp.net/wiki/Skyrim:Respawn

Most dungeons normally respawn after 10 days. Cleared dungeons respawn after 30 days. Some dungeons don't respawn at all, though.