How to disable gprs, umts (3g) connection?

With a 3G phone, you can turn off 3G network access but doing so does not prevent access via EDGE or GPRS.

I believe the only way to completely disable data/internet access via the cellular network is requesting this for your line/account with your cellular provider.

There are none. 3rd party apps cannot affect system settings, so there won't be any unless Apple alters the SDK to allow that.

Keep in mind that both data and voice are carried on the UMTS network.

The option to turn off Data Roaming (Settings > General > Network) will prevent data access on networks other than your primary carrier's.

The 'ultimate' solution is Airplane Mode, with Wi-Fi turned back on - but, that blocks both voice and data on all cell networks.

In phones from ATT there is is a feature in Settings / General / Network called Data Roaming, which can be turned off. I'm not sure if that exists in phones sold thru other carriers in other countries.

Ok, I see.

No option for a "all you can eat" data plan with your carrier?

It would seem the iPhone would not be the best choice of phone where the tariffs are so stiff. This phone virtually thrives on data for so many of its cool features, and without data, you might as well have a cheap Razr.

There is not a way.

The iPhone is designed to always have internet access as long as you are connected to an available wi-fi network or have cellular reception.

If you don't want data/internet access via the cellular network, it is all or none. If you don't want this, you must contact your cellular provider and request that data/internet access be completely disabled for your line/account.

I have a 500 MB limit too, but I have WiFi at home and at work. On my last bill I only used 174 MB.