have a field in your user table to keep track of the login
info, something like LOGIN and the datatype can be number(access)
or bit(SQL), it will store only 0 or 1. 0 not logged in, 1 logged
in.
Then on your login form where your user logs in add a sub
routine to update that users column from 0 to 1 upon a successful
login.
On any other page you can create your graphic or whatever to
show they are logged in. You do this by creating a recordset of the
user.
Then wrap you "online" graphic/text around an IF statement,
saying
if rs.fields.item("login") = 1 then
show the graphic/text
else
the user is not logged in
end if.
On your signout page make sure you put a subroutine that sets
that users LOGIN value from 1 back to 0.