Ayman,
If it is something that identifies the user, you can store it in a cookie and query that on page loads. OpenACS does that for user_id. The other option is to store it in the database, and query based on user_id.
Other than that I can't think of any way to pass information between pages. That is the way HTTP is designed. There are two operation that are mostly used GET and POST. GET passes the parameters in the URL and is used to retrieve information. POST uses form variables and is used to trigger a change, for example, inserting, deleting or updating a row in the database.
