It lists your GPRS connections, and allows you to disable them so that they won't be used.
Disable your connections before you leave, re-enable them when you return - piece of cake with MoDaCo NoData
Note that if you get bizarre registry errors on toggling, you need to app unlock your device (e.g. with SDA Application Unlocker).
Enjoy, feedback welcomed! If you use the CAB, please consider donating £1 to my 'quidapps' effort to develop cheap, useful applications and tweaks - click here to donate. Donations will be used specifically to buy development tools to enable slicker and more advanced tweaks and applications in the future while retaining a £1 price point!
[Edit 15/01/08: Now added Smartphone support (finally)!]
[Edit 29/03/08: Minor update]
nodata.cab 25.23K 72023 downloads