Some of AT&T's earlier 3G cards only had the 3G frequency they use domestically (850/1900.) The later 3G cards are mostly tri-band for using 3G internationally.
On GSM world it shows Netcom and Telenor Mobil use 2100 mhz in Norway.
On ATT.com it shows the Sierra USB 881 with:
# Tri-band HSPA - 850/1900/2100 MHz
# Quad-band GSM/GPRS/EDGE - 850/900/1800/1900 MHz
Per Verizon's website you have to use two cards. A CDMA Pc card for US and a GSM based card for international.
http://support.vzw.com/faqs/Internat...al_access.html