would a usb wireless n adapter work with a 60 and a 80 gb ps3. I want to know because my network only allows wireless-n. 

What kind of router do you have?

Does the PS3 not support N?

I wanted to know your router so I can try to find a setting which would allow your PS3 to connect directly to your router.

You can't use a USB network device on the PS3 (outside of Linux) since you won't have the drivers for it.

One option you have, if you truly cannot connect to your network directly, is to buy a second wireless router which would sit near your PS3 and be connected to it via an ethernet cable. That second router would then be configured to communicate with your main router.

I have a dlink dir 655

also I am my family's network I.T.
My setting in my router only allow wireless-n because I want faster file sharing and further range.

I am not familiar with that router.  I have a linksys N and I allow B/G/N.  I configure the individual computers to connect on N if their adapters are capable of it.  My PS3 connects at G.

From your user's manual page 29 ftp://ftp.dlink.com/Gateway/dir655/Manual/dir655_manual_100.zip

Under your Wireless settings:

"802.11 Mode: Select one of the following:
             802.11g Only - Select if all of your wireless clients are 802.11g.
             Mixed 802.11g and 802.11b - Select if you are using both 802.11b and 802.11g wireless clients.
             802.11b Only - Select if all of your wireless clients are 802.11b.
             802.11n Only - Select only if all of your wireless clients are 802.11n.
             Mixed 802.11n, 802.11b, and 802.11g - Select if you are using a mix of 802.11n, 11g, and 11b wireless clients."

Make sure the highlighted one is selected and your n devices will work at n-speeds and you g devises will work at g-speeds.

EDIT: By the way, you have a new firmware that came out last week that fixes speed issues:

http://www.dlink.com/products/support.asp?pid=530&sec=0#firmware