I have a great functioning 5820 (5810) given free by the phone company with a cheap $10 subscription.

Very impressed after a month and now want to upgrade the device to a 7290. Would be nice to sync my calendar via USB and use the phone functions.

Can I buy an unlocked newer one second hand and just put in my existing SIM card as you would with a normal GSM phone?

Or do I have to register the device with the phone company? If so I thinK i would buy a new one...

Advice please

Be very careful. There are lots of disappointed eBay BB purchasers. Broken BBs. Keys not working, etc. And the biggie - "unlocked" BBs which were actually locked.

So, having said that... You can move the SIM - I do it all the time - but you have to be carefull. Do you want to use BWC e-mail; there may be issues registering the BB on the BWC if it was previously used. Manageable, but a pain.

Personally, I would find the best price and buy a new one...