Can I move tempdb?

You would use the 'ALTER DATABASE' statement

ALTER DATABASE tempdb 
MODIFY FILE (NAME = tempdev, FILENAME = 'E:\SQLData\tempdb.mdf');
GO
ALTER DATABASE tempdb 
MODIFY FILE (NAME = templog, FILENAME = 'F:\SQLLog\templog.ldf');
GO

TempDB is recreated every time the instance of SQL Server is started, so there is no need to move the physical files. When the instance is restarted the files will be created in the locations specified.

Until then tempDB will continue to use the data and log files in the existing location. Once the instance has been restarted, you can safely delete the old files.

Further info can be found here on MSDN.