How do I set up a Wireless router connected to a cable modem?

I have a cable modem which is connected to an eight port ethernet hub. I would like to add a wireless capability and have a spare Linksys WAG54GS wireless ADSL modem/router that I believe should be able to do this for me.

How do I set up the Linksys router to ignore its ADSL capabilities and provide a Wireless access point only?

Presumably I will need to change some settings in the Linksys router but will I have to change anything in the cable modem too or, as it is downstream of the modem, will it be ignored?

Help and guidance would be appreciated.