I've had this happen twice now, and it takes a lot of battery pulls to get it sorted (currently still not sorted at the moment).
I believe this is something to do with the sim card not registering properly, its happened in the UK and also now in France where I'm roaming.
The phone sometimes works ok but I cannot access my mailbox for my emails (gmail, hotmail and others etc), or BBM (sometimes says exception, RIM crashed etc).. nor can I look at txts..but I can still call.
On other occasions after restarting it just crashes completely and no icons will work, effectively its frozen.
Why does this happen? How can I prevent it? It seems to happen randomly, it is not linked to anything I do, as I was receiving emails fine this morning in France and suddenly it stopped working and I had to restart it.
Any help greatly welcomed, as I am using my phone for my business and as I am abroad it is especially inconvenient. I recently swapped networks and seriously considering going back, as I never had this problem with the other network. 
Hi cluurr,
Thanks for your post here.
To be honest it sounds like an issue with either the software on the phone or the phone itself rather than a network issue.
The first thing that I would do is try a software upgrade by connecting the phone to Desk Top Manager via a PC and try to update the software.
If this is up to date then the next step would be to send the phone away for a free of charge repair once you are back in theUK.
James
