I typically switch between different SIMs on my phone for travel, so I just use the eDGe slot to store the SIM that I'm not currently using. Otherwise I tend to lose the darn thing! Of course then I spend hours looking for the other SIM because I forget I put it in the eDGe.

Seriously though, I thought I saw someone on these forums saying they got a SIM to actually work on the PE for a 3G connection. Any credible reports of this? I just recently acquired a PE (couldn't resist the $200 price) myself, but haven't played around with it.