Information about active connections for DBs

SELECT * FROM master..sysprocesses

SELECT db_name(dbid) as DatabaseName, *

FROM sys.sysprocesses

WHERE dbid > 0

and db_name(dbid) = 'vm5' -- if filter by DB name is required

SELECT db_name(dbid) as DatabaseName, count(dbid) as NoOfConnections, loginame as LoginName

FROM sys.sysprocesses

WHERE dbid > 0

GROUP BY dbid, loginame

order by db_name(dbid), loginame

sp_who 66
go
--kill 66
go


http://msdn.microsoft.com/en-us/library/ms179881.aspx