I talked to my current cell provider (Einstein PCS, a local company in WI, USA) and they offer a $5.95 unlimited data plan that uses GPRS mostly and EDGE on a few towers.

I'm not very familiar with cell data technology. Will this work with the n900. Are there frequencies or other details I need to check to find out if it will work? Is GPRS too slow to be useful?

This will work with the N900 fine as its a standard Quad Band GSM unit. To be honest trying to browse the web will be painful over GPRS. It should be fine for sending and receiving emails though. EDGE is passable but obviously 3G is best if you want to do VOIP/Skype etc. If its your only option I hope you have good wifi at home and at work/school.

GPRS is too slow. EDGE is OK for simple websites, but it's no fun watching YouTube on EDGE. Internet radio with 128kbps or below works well on EDGE.
AFAIK, the N900 is quad band for GSM so there shouldn't be a problem with the data plan.

The N900 supports

Optimized for WCDMA 900/1700/2100
Quad-band EGSM 850/900/1800/1900

# GPRS class A, multislot class 32, maximum speed up to 107/64.2 kbps (DL/UL)
# EDGE class A, multislot class 32, maximum speed up to 296/177.6 kbps (DL/UL)
# WCDMA 900/1700/2100. Maximum speed PS up to 384/384 kbps (DL/UL)
# HSPA, maximum speed up to 10 Mbps (DL), 2 Mbps (UL)

As long as your provider is operating a GSM service on 850, 900, 1800 or 1900 mhz frequencies you should be able to use the N900 with EDGE and GPRS.

Anyone using the N900 with AT&T and many T-Mobile subscribers (myself included) will be using EDGE. Personally I want more speed but I will take what I can get. For faster downloads you can use WiFi hot spots that may be available.

Also, in theory using EDGE only will increase battery life (assuming you can disable 3G radio)

To give you more information about the speed, here's a quick summary:

GPRS -> EDGE -> 3G -> HSDPA

GPRS being the slowest.
HSDPA also known as 3.5G is the fastest on the market.

The N900 supports all 4.

This theory is 100% correct. On my E71 in NYC:

(not constant data, just checking email every 30 mins, total 20 mins browsing, 20 mins talk)
9am - midnight: 3G = 60% battery left
9am - midnight: switch to GSM (EDGE) = 85% battery left

I concur, my N82 will last 2-3 days with the 3G disabled, around a day with it enabled.

I found in the n900 manual where you change the settings:

Settings > Phone > Network > Manual > yournetwork > change from dual to GSM.

I'm hoping one create a toggle icon on the desktop to turn from dual to GSM and back.
Kevin

This might be an stupid question, so please bear with me. Are there HSPA bands?
I live in Mexico and hence are limited to these 2 GSM carriers http://gsmworld.com/roaming/gsminfo/cou_mx.shtml
I'm currently a "movistar" subscriber, all the technical information they publish about their network is that it is "GSM 1900", commercially they say they have "3.5G". I currently own the N800 that I connect to the Internet using EDGE from my SonyEricsson K750 via Bluetooth.
In case I can talk myself and Santa Claus into getting the N900.
What kind of speed would I get if I put my current SIM card on an unlocked N900?
I hope my post don't confuse you and you could provide some insight into this doubt that's keeping me awake at night