Unfortunately not. The password is used when you come back from screen lock. Best you can do is put your Security Timeout to 1 hour, but either way, it will continue to lock.
Why would you want to only have the password enabled upon booting up the device. If you dont let the battery drain and your lucky enough not to have any reboots, then your device may go weeks without a reboot. That would defeat the purpose of having a password in the first place.
Damn. That's annoying. I would like a password only on boot up (like every other phone I ever had) in case someone steals my phone or I lose it. Its bound to freeze on the new owner at some point. And after their battery pull.... Bam! Password!
Posted from my CrackBerry at wapforums.crackberry.com
By then it would be to late. Most people never turn off their BB and if someone steals it they are most likely going go get all the info they want before shutting it off. Most companies have passwords set up in a global policy to prevent this.
I just set mine up with an extra long timeout, an hour I think. This way it doesn't get super annoying, but will lock eventually if I haven't used the phone. It just helps when someone is always slow replying to an IM, I can carry on and do other things but not have to unlock all the time.