I just picked up my Mini a day ago. Everything was running fine except my wireless connection. I could see my router but whenever I tried to connect it would tell me I was out of range, even when I was right beside it. I was able to connect to a few open networks, but they wouldn't stay connected for long. I tried a number of things that didn't work (updating the driver, reseating the card, trying another wirless controller from the Dell site).
Finally I removed the security from my wireless router and connected that way. Then I re-established the security and then it connected fine. Now it seems to be working with no problems. Don't know if it was a combination of what I did, or something in the security settings on the router....but it's worth a shot.