Sql Express 2005 Synchronization --> Asp.net 2.0 Framework

I have to develop a web application and I have the following questions:

Technology thinking of using
ASP.net Framework 2.0
MSSql express edition 2005

In the architecture design we decided to go with an offline approach. Meaning that we are going to have a server with an IIS at the Local Offices and one remote server in a web hosting  environment. Both Server are going to have MSSql Server Express Edition 2005 and are going to get synchronize with each other. So the user can choose either to work with the remote server or the local server.

1.My question is whether you have some ideas of how to synchronize the 2 sql express servers and how to use the locking of certain records in order to do that.
2.Is it better to go with PHP aand Mysql technology?
3.How can I connect a remote server with the local server. What do i need ? What do i need to ask the Web Hosting Provider in order to be able to connect to the remote sql express server and syncrhonize it with my local server?

Thanks