Don’t worry if you left your Nokia E61 somewhere in your office or home and don’t want any unauthorized person to access it. Just send a password from other phone, so this tips guarantee that the phone won’t be open whatsoever. The phone will be auto-locked (or auto-unlocked).

Here the step by step way on doing it:

1. Go to Tools > Settings > Security Settings > Phone and SIM
2. Change “Allow Remote Lock” to Yes
3. Insert a password, contains 5 characters as minimal
4. Put a password again for verification

Not sure whether this way still work for other Nokia phones or not.

[Kompas via 3Gweek]