[ultrageoff]

I was wanting to do this and came to the forum after a search. There have been a few threads on this already, none of which seemed to provide a decent workaround for the absence of this (rather basic?) feature on the BB. So, I thought I'd post my own best effort, which is:

The easiest way I know to transfer your address contacts, or at least the names and numbers, to your SIM is to borrow a phone that syncs to Outlook. This includes most Sony Ericssons and, I'm guessing, most Nokias too. Go to the Sony Ericsson (or Nokia, or whatever) site and download the relevant PC synching software. Back your friend's data up, either by using the software you just downloaded or by making sure all his/her data is on his/her SIM. Put your own SIM into your friend's phone (take their SIM out). Next, synch your Blackberry to Outlook. Then, synch your friend's phone to Outlook using the manufacturer's synching software, displacing your friend's data with your own. Then use the phone to transfer your contacts to your SIM. Transfer your SIM back to your Blackberry, put your friend's SIM back in his/her phone. Restore your friend's data from the backup you made earlier, if necessary.

Summary, the easiest way to do it is to get your contact data onto a phone that can transfer contacts to a SIM (that's most of them). Obviously, any of the above is at your own risk. It is a good idea to have a basic set of contacts on your SIM, because your BB might be away for repair at some point and a cheap phone with your data on the SIM is way better than one without it.