This notebook must be available on the network. Clients must have appropriate SQLNET.ORA and TNSNAMES.ORA files which would point to the database on the notebook. More or less, the whole thing should work as if the database was on a "real" database server.
You should, perhaps, take care that notebook has a static IP address. DNS would probably not be a good idea.
Speaking from my point of view, wireless connection isn't satisfactory enough when speaking in database terms. If anything disturbs your connection in the middle of processing, during Forms or Reports session etc., it will soon become real pain. Been there, done that. I'd rather use cable connection.
If both Notebook and PC run MS Windows XP, they will probably "see" each other as soon as you plug network cable into network cards. Set their IP addresses; check whether they are available using PING command at the command prompt.
Database Notebook must have a listener running, client PC must be set up in order to see this database. Basically, not a big deal.