new cron-jobb?

[pyd]

I need a new cron-job.
It should check every night for users that have not logged in for 30 (or x) days, and send them a email to request them to login.

After 60 (or x) days, the users should be moved into a seperate usergroup.
Also, the user needs to be flaged in some way to prevent the user from reciving a email every night...

Have someone done this before, or can someone help me with this?

sample-code

if logindate < 30 days and logindate >60 then
send email.
ElseIf logindate < 60 days then
send email and change usergroup
end if