Hi there,
A session ID is, as far as I remember, around 20 chars. It can look like this:
7b09fbbdaf767c6c83728c7cacbf0403
If a user has to type in that, I think he would go mental 8-)
Another thing is, that a session ID is temporary. It only lasts until the the browser is closed, or user has been inactive at your site for some time. Then when he goes back, he might get a completely new ID.
In stead, how about giving your user a set id, which could be a simple integer.
Did that help?
Jens