I want to convert WRT54GS to an access point...

And have it work with WRT310N Router. Is this possible? I have a 3 story house and for now the N Router is on the top floor in one corner of the house. While I want the WRT54GS to be on the main floor as an AP. The bottom floor isn't needed for now.

The N router can barely get a signal to my desktop on the main floor on the opposite end of the house. If I'm in my kitchen which is below the N router room and to the right I get a halfway decent signal.

Linksys pages aren't helpful and all the threads I read here suggest 3rd party software. Before I go about doing that, I wanted to be sure the WRT54GS would work as an AP with WRT310N. Please Advise! Thank you

It depends on the setup.If WRT54GS has a feature of repeating a wireless signal then it will work otherwise you need to hardwire the WRT54GS to WRT310N for it to act as an AP.I've been a linksys tech support before.As far as I know linksys WAP54G were capable of having wireless repeater function.You can also try WRE54G Linksys range expander.No need for 3rd party software.

I just checked my resources and the WRT54GS router does'nt have wireless repeating capability but Linksys Access points only(e.g WAP54GS).On the other hand, if you're not sure of the wiring within the walls, then better use a range expander WRE54G.

Yes It can! any wireless router,irregardless of the brand can be converted into an AP.You just need to change its LAN IP address and disable its DHCP server function.Catch is, not all of them has a repeater function.Therefore it can't be a stand alone device.It's AP function will be possible if hardwired to a regular router/modem.I used to be a Linksys tech support and only WAP54G AP's can work as a stand alone device for repeating of signals.