[Web4lib] script recommendation

[Sigrid Kelsey]

Can anyone recommend a "who's on IM" script?  For example, a library patron
could access web page with a list of staff and IM anyone who had a green
light next to their name- and a red light would appear for librarian who are
not at their desk or logged off?  My gmail does this.

Preferences would be works with GAIM, uses PHP, and is free and open source,
but any suggestions are welcome.
thanks-
Sigrid Kelsey