6086 has Wifi capability (UMA- unlicensed mobile access). This means that you can hop on wireless networks and make/receive calls without using your minutes. It also lets you surf the internet without using airtime/media charges.
The biggest card that can fit in these is a 2GB microSD card. I'd suggest meritline.com. You can find a 2GB Sandisk on there for $30. Better than anywhere else.