miscro SD slot work as :

1. another picture viewer when u re traveling and ur DC is ran out of battery.
2. memory expansion slot for holding some large size map file like Europe countries map. (build in memory is 2gb, some map file migh up to 1.7gb)

yes.. normally we dont need micro SD.. just plug and ready to use...

http://www.garmin.com/garmin/cms/site/sg/support/MapUpdate/

this is the url for future map update, plz update malsingmap only (ignore city navigator as it is useless)

yes... u need a mini usb cable for connecting gps and pc.
this type of cable is very common , normally same as the digital camera / external HDD devices.
if u really dun hv, u may just get it from any pc shop will do..
i believed it just cost ard ten bucks only.

cheers and enjoy ur new toy ^^