client server application using VB and SQL Server.

Hiii,
I have to develop a client server application using VB and SQL Server,I would use ADO.I have to make an online admission system where around 10 students can be given admission at a time for some specific college and course, after checking that whether seat is availabe in that college for that course or not.10 clients will access database(they can request to add,update,delete data) placed on a server.What are the major points I have to take care of for creating this application.Plz tell me that which cursor and lock type I'll have to use for:
1. Add record (by one or many users at different or at the same time)
2. Update same or different record(by one or many users at different or at the same time)
3. Delete record under same situation.
If A,B,C,D are users.Can the record can be viewed by any no. of users(clients) without any problem?But how to restrict other users(B,C,D) to update/add/delete a specific record if that record is being used by a user(A)?And processing should be fast without getting an error/corruption of database/data duplicacy/data redundany. what about transaction handling?
I have worked only on desktop application using VB and SQL Server..At what points this client server application will be different from desktop application??
Please help me in this regard..Its urgent for me.


thanx :)
mamta