Best Data SIM for Germany

[inquisitor]

The missing support of the 2.1-GHz-band in your phone makes it difficult to give you advice. All German discounters, that offer those € 0.24/MB are based either on the eplus network (Aldi talk aka Medion Mobile, Blau, simyo, solomo) or the O2 network (Fonic), which both do not support EDGE yet (O2 has recently started a hesitant EDGE-rollout).

So if you're looking for more than GPRS-speed, you need to go for a T-Mobile or a Vodafone-based provider as only those already provide nationwide EDGE-coverage.
In this case the cheapest providers are either ja!mobil (sold at REWE-supermarkets) or pennymobil (sold at Penny-supermarkets) with € 0.35/MB (after activating the "ja! mobil surf"- respectively the "pennymobil surf" option online or by customer support, otherwise € 0.49/MB is billed) or a plain Vodafone CallYa SIM, through which you can get unlimited web access for 24h for € 4.95 (so called WebSessions).
T-Mobile has a similar offer to the Websessions, but they charge not by 24h but by calendar day, so T-Mobile is less attractive as long as you don't start sessions exactly at midnight.
Fonic (O2-based) will also start a dayflat for € 2.50/day on September 15th and they will sell their SIM bundled with a HSDPA-USB-stick for € 89,95 (http://www.fonic.de/html/surfstick.html). But I don't know if this bundle will be sold at retailers or if it can be ordered online only. Anyway, that's presumably a too big investment for 2 weeks.

[GreyPaint]

Thank you. AT&T turns out to have a decent roaming deal - $30 for 20MB, which should be plenty considering the hotels mostly have WiFi (which the phone also does.) Would you expect the Nokia N95-4 to be able to use AT&T for data roaming?

Thanks