What services should i disable?

[superbay]

Hi all.

I just got my new HTC Dream yesterday but i have a problem. I'm using the postpaid service from the local GSM provider. That means i must buy voucher regularly to fill my account. I already disable the Gmail sync so it would not suck my account credit. But apparently, my account credit still decreases.

I wonder what other services i should disable to avoid such thing happens. I'm very new in this android thing so I need to know the detailed explanation about it if youguys dont mind. Any help is appreciated. Thanks