I also have an android based samsung galaxy spica on a vodafone bangalore prepaid connection. For me also i can browse the net using the browser but none of the other applications are able to access the net (like maps, twitter etc even https pages).
I think vodafone only allows port 80 access on their vodafone live. I will try vodafone Mobile comnnect and let u know ...
As of now they are quoting some exorbitant rater like 10 pais / 10 KB = RS 10 / MB = RS 10000 / G