sysprocesses is a server-level view, it's not database-specific. It returns all of the sessions connected to the server and, as one of the columns, has the id of the database that the session is currently connected to.

select * from master.sys.sysprocesses

where spid>50 -- don't want system sessions

and dbid = DB_ID(<name of database in question>)

I'm using sysprocesses (a compatibility view) because I don't know how to get the DBID of a sleeping connection via the 2005 DMVs