Install Titanium backup and see whether or not it starts nagging about root
. If you can make backups: you've got root!
If not, the app will tell you it needs root access!
A bit cumbersome perhaps, but it gets the job done!
edit: Oh yeah, it's possible to un-root the phone again. E.g. by flashing an official HTC ROM on it again, then you will have to root again as far as I know!
ROM: OpenSensation (20121108)
Kernel: TamCore 3.0.51
Old: Qtek s100, Qtek s200, HTC Touch, HTC Touch Cruise, HTC Diamond, Samsung Omnia, HTC Hero, HTC Desire