“Okay, so I know this thread is old, but up to last month nobody had posted a solution to using the internal airport card to share the connection so I said i’d register incase anyone else was googling endlessley to find a solution.
Turn on Internet sharing:
select the network you want to share and share it via airport and give your network a name… set up a 5 digit WEP key if you want protection.
open terminal and type ifconfig en1
This will give you your router number, mine was 10.0.2.1, it will be listed next to the word inet
next type dig, this will give you your ISP’s DNS numbers (at the very bottom, next to the word server)
On your PS3 open the network settings, scan for your new network, enter the WEP key and configure the IP manually.
Under IP type the router number but add a digit to the last number, in other words, my router was 10.0.2.1, so I assigned my PS3 the IP 10.0.2.2
use the standard subnet mask of 255.255.0.0
enter the router number you found (10.0.2.1)
enter the DNS numbers found earlier.
MTU = Auto
Proxy Server = Do Not Use
UPnP = doesnt make a difference
and thats it, your done… im using my PS3 with my 3G mobile broadband shared via airport.
EDIT: After a PM I realised I completely left out the Airport settings part.
In Airport settings under TCP/IP select configure IPv4 via DHCP, and under DNS add your ISP’s DNS numbers that you found earlier.”