SIM card for broadband in europe

Hi. I'm going to be traveling all over Western Europe this summer, and want to take my laptop so I can blog about our trip. I don't want to be tied to internet cafes and wifi hotspots, so I ordered a Laptop Stick from T-Mobile, and was told to get a European SIM card for it when I get there. I will be in Amsterdam for the first day and need to find a T-Mobile or Deutsch Telekom shop, but I can't seem to find any. The other (and more preferable) option is ordering one before I go so I don't have to waste vacation time on it and risk not finding what I need. Any suggestions?