This paper discusses the mobile Internet access in the context of project BAS (Business As uSual), which plans to develop a system that connects all the public service buses as nodes in an ad hoc network and use this network to provide a wide range of services that are perceived to be useful to commuters. In our system, the heterogeneous communication between wireless bus ad hoc network and Internet is established with the installation of specific access routers along the roadside, which serves as gateways between these two types of networks. However, the Internet integration of wireless bus ad hoc network with the Internet faces many challenges, such as gateway discovery, mobility management and the routing procedure. In this paper, we propose an architecture that addresses these issues. Additionally, this architecture allows passengers to access the Internet with their mobile devices by usingvia this bus ad hoc network, thus and possibly reducing their access and usage costs greatly.