Is 2100 MHz-frequency band all you need?
 

From reading this thread, it looks to me as though all I need is a device that will tether and that has the 2100 MHz-frequency band for 3G data in Germany. Is that correct? Most of my devices/old phones, etc., have that frequency. I may just get one unlocked and use that with my computer. I'm also thinking of getting one of the unlocked Novatel MiFi 2372 units so that both my husband and I can use it. That has 3 frequencies for 3G - 850, 1900 and 2100. Do you think that would work?

Well you dont have to buy another cell phone to have data in germany with your iPhone. You can use SIP to have 3g,wifi and calling access. It will work even if your iPhone does not have a sim or even if it is locked with at&t. I have heard that at&t has unlimited data plan come 2011 im not sure though if germany is included with the plan. Happy New Year everyone!

Thanks, but I don't know what [those] are. Can you please explain a little. Thanks.

PS - ATT used to have a required unlimited data plan for the iphone (domestic only), but they have just done away with it when they started to allow tethering on the iphone 4. The unlimited was for domestic data only - not for roaming internationally. The new data rates are horrendous. A more reasonable plan would be much appreciated.

yes, you are right, you can use any phone with 2100 MHz 3G, all you need is to buy a suitable SIM card (there were some threads here already covering this topic)

Chris

You obivously have never been outside the US, neither have you heard of roaming fees. Your advice to use data on roaming can actually ruin people!

[It] is just an app to place phone calls through VoIP (internet-based telephony). It's good to make cheap phone calls, but it still requires 3G- or WiFi-connectivity to establish an internet connection, which in fact it does NOT replace.

Also AT&T data plans do NOT include data usage abroad. Actually data usage on roaming is astronomically expensive.

So artbytes is on the right track when looking for a German prepaid SIM, that she can use in her MiFi device.
Btw dg7feq is right - in Germany 3G is operated by all four operators (T-Mobile, Vodafone, O2 and eplus and all the MVNOs on these networks) exclusively at 2100MHz, so this is the only frequency band your device needs to support for 3G. Outside of 3G coverage German GSM (2G) networks use GSM at 900 and 1800 MHz, which nearly every device supports (the iPhone and the MiFi definitely do).

Frequency Bands in Germany and Austria
 

Thanks so much for your answer. That helps a lot. It looks like I'll be fine with the devices that I've got now that are already unlocked. That's good news. Now, I'll just need to get the SIM cards - and it sounds like they are readily available.

I am sorry for my ignorance and thank you for giving out a detailed explanation. You have enlightened the situation. Thanks

Actually, that person is in the Philippines

I see. And this person happens to be the developer of the suggested app or why have you removed the brand?

@inquisitor

Speaking of a phone suggestion, or rather a phone offer, I sent you a PM. I hope it reaches you on time