in reply to Don't want to wait

t0mas gave you %95 of what you need. Use system to do the calls you need, just add the & at the end of the system call and your perl program won't wait for them to complete before proceeding. If you use exec control will never return to your perl program. Alternatively, you could do something with fork in your perl program, but that would be uglier and not really add any benefit.
system "mhmail someone@somewhere.com -body $meg &"; system "get_mail &";