USB Solution (hardware)

I want to know wich IC is used for convert digital level output to USB format? For example, MAX 232 is used as interface another device to PC through COM Port(ie RS 232 format). Similarly I want to connect my mobile phone to PC, through USB port, to connect Internet. I have constructed similar Interface for Digital Diaries using Max232 IC. Pleasee suggest me where I can get the details for that? Iwant the full details about that. is Max232 suitable for this? If yes will I get propper bandwidth with this.

Thanking you

Suchith Das