GUID - in the PK field - Shared Database

[tinkertoy]

I have a database that resides on a server, that will be shared with others. The others will be accessing the database from a PDA that will be synchronized either wirelessly or when back in the cradle. The database is converted to the PDA database program, and in order for it to synch up, the primary key on the parent database has to be text. On the PDA this becomes a GUID, which then creates it's own version of a autonum. Because the secretary will be updating the database from her PC, the PK in the table stills needs to create an unique ID for each record. The db table field is a PK, and data type of text, no duplicates not indexed. I expect from the form on the Access 2K frontend db that I can create some code, that on "new" form the PK field will create a unique identifier, GUID. But, I don't know what the code should be. Can anyone give me a piece of code that on new the field will generate that ID?

Thank you in advance.

tinkertoy