Unix 'finger' equivalent

Via a previous chain I learnt that you can find the IP of a logged in
user by doing a 'net send <user> ""' followed by checking the NetBIOS
Remote Cache (nbtstat -c).

Is there a way to also find out if the user is active (or his idle
time)?

More generically, is it possible in a Windows network to find the Unix
finger information?

Thanks in advance,
Sharad Agarwal
PS: I suppose we could do it by running a 'finger' service on all the
desktops, but I am looking for a way to do it without additional
software on the target machines.