Kotonokia,

Lots of questions bud.
First the cards, you need them.
Go to google type in 2,4,8 or 16gb sdhc cards and at upper left you will see shopping click on that and presto it will show hundreds of vendors selling sdhc cards. You can also go to www.pricegrabber.com and type in 2,4,8 or 16gb sdhc cards and it will bring you most reputable dealers selling at lowest prices. Read every comment about vendor before you buy!
Next download the latest and greatest update os2008 and install it. If you can't take it to a computer store and for $30 they will install it for you. If you live in NYC or Chicago go to the Nokia store and they will do it for free.
Play with it for a couple of days checking out the apps that come with os2008 and then go to www.maemo.org and get lots more apps to make your new tablet humm. Then start reading these threads and ask questions when you get stuck.
Hope this helps bud. Dan lol