remotely getting the users database connection string

hi, iam using asp.net 2.0 with c# with sql server2000.
when user logins to my website i want to acess  the users  local database, all user having the same database name, same tables every thing  but but they are not connected in network    .so i want to know how to get the data source value in the connection string for that user, so that i can acess his local database.
can you give example which helps me