converting 2Tier Applicatio to 3Tier

I am programmer and assigned a assignment.
In my organization there are 200 users working in a client server architecture.Front end application is developed using VB 6.0 and at the back end we are using Oracle 8.The database connectivity is done using DAO ODBC Direct.
every user first connect to the Oracle Server and then he operate his work.
we want such a middle tier server which only connect the database with oracle server and all the users only connect the middle tier and so they can save thier time of connection and also they use only internet browser to work with our application i.e there is no need to install all the software on every user's machine.
please tell me which type of middle tier we need?????????
and what is complete method and solution of this problem??????

Kashif Khan
Email [email protected]