Using your PDA/phone to connect to the internet via laptop

[pacman160778]

As the title says, i want to connect to the net using my HTC Touch Cruise (aka O2 XDA Orbit II).

I have the connection set up and can connect to the internet using it (i'm using it now to type this), but i'm afraid of getting crazy bills.

I've been doing it on and off this past couple of months, and have been keeping a close eye on my online billing and i'm not getting charged for it at all, which i find strange.

I have the free internet bolt-on (i'm on an O2 contract), but Car Phone Warehouse are telling me that using the phone as a modem is not included in the free data usage. Yet its still not showing up on my bills.

Does anyone have any experience with this?

The only internet connection i have in the house is one of those '3' USB Modems on contract but it only has a 5Gb usage, so everything over that is 10p per Mb, which is why i'm using my PDA to connect my laptop as it appears not to be charging me.

Any advice/info would be greatly appreciated!