Records in CRM 2011 can either be user owned or team owned.
A default team gets created when a business is created with the same name. The users that are in business unit automatically become member of that default team.
Default team cannot be deleted, renamed, moved to other business unit.
We can neither add nor remove member from the default team.
We can write dialogs and workflows against team
While creating a new team we need to specify Team Name, Administrator and Business Unit.
We can also specify Default Queue for the team, if we do not specify and save the record, queue with the name same as Team name gets created.
Team can now be deleted (except default team which gets deleted when we delete the business unit). To delete the team, we need to first remove all the records owned by the team by either deleting those records or assign those records to a different owner.
We can also use Reassign Records option to reassign them.
If we try deleting the team that owns the record we get the following error
The team record got deleted after I re-assigned the record owned by the team.
Finally few things to remember while working with team
Hope it helps.