They charge as many connections as sessions you've established. Theoretically a session could last days, but practically it will be interrupted at least once per day. If you move with your phone during a session and so lose the signal for a moment or if a bad handover occurs, the session will also be interrupted.
Another problem I fear is, that if you initiate a session through your computer, it'll be closed if you switch it off. Most mobile phones (like my Nokia N95) will keep the session alive even at idle, if it has been initiated from the handset itself. But I don't know if you can join a handset-established session without interruption from you computer.
Against this background the ICQSIM seems more attractive me, as they charge only a daily usage fee of € 0.39 instead of session fees.

The connection fee is what scares me. Imagine putting the SIM in a device which uses Microsoft Push Mail technology.

I agree, so I'm hoping to hear what others have been experiencing with session charges on a real-world basis. As Inquisitor said, a session could theoretically last days assuming you don't lose coverage at some point or turn the phone off. So all the push Mail wouldn't make a difference- or shouldn't.

Anyone? What have the bills looked like for casual data use in Europe? How many session charges typically in a day?

Kupe

What i found out is that the number of session depends on the network, on the mobile device and also if you are moving or stationary.
This makes it quite hard to estimate.
Our company builds gps-tracking devices for vehicles and personal use - we have between 5 and 25 sessions a day depending on the conditions (for always online application).

The session is on hold from the network if a handover is not successful or if you drive into a tunnel or out of coverage. Depending on the provider it times out after several minutes.
T-Mobile D for example keeps the old session open for 45 minutes - if your device reconnects to GPRS while this timeout the old session key will be used and thus no new connection fee should be charged.

Chris

I have been using my 423 sim for data and found that despite the 1.49 being the cheapest around, by just surfing through pages as I normally generally do it seems to cost about 5 Euros for about 10 minutes of surfing. (I wasnt downloading photos music or videos - just browsing through sites for booking tickets etc)

I wonder how many kb a standard webpages uses?

to give you some hint i checked the size of the starting page of some pages:

www.cnn.com -> 850 kbyte
www.google.com -> 21 kbyte
www.prepaidgsm.net -> 94 kbyte
beijing2008.com -> 370 kbyte

to save traffic when online from mobile deactivate images and flash.
then the CNN website for example comes to: 90 kbyte (which is 10% of the original value!)

Chris

I find content compression to help a lot on wireless connections. It can also save you a bundle while roaming.

For the geeks among us there is ViCompress (http://www.visolve.com/vicompress/), a free Linux compression and caching proxy you can run along Asterisk on an old PC.

Those requiring plug and play solutions can always go to service providers such as Propel (http://www.propel.com) which costs $8/month or $60/year.

Also, Opera Mini does some level of compression. It's also one of the best mobile browsers out there.

Great point. Opera's back end servers do the same thing for Opera Mobile and OperaMini for mobiles and SmartPhones as ViCompress and Propel do for desktops.