First go to the "How to make your Mac into a WIFI Hotspot" page and follow the instructions.
After your WiFi hotspot has been created, turn on 'Internet Sharing'.
Now open the 'Terminal' in the utilities folder in your 'Applications' folder and then type this exactly as shown in to the terminal:
cp /etc/bootpd.plist /tmp/bootpd.plist
Hit the Return key. It may seem as though nothing has happened. That's OK.
Turn 'Internet Sharing' off.
Go back to the Terminal window and type:
open -e /tmp/bootpd.plist
Hit the Return key. A file will open in TextEdit. Locate this section of the file, near the end:
Change 4 to 0 and then hit Command+S to save the file.
Go back to the Terminal Window and type:
sudo cp /tmp/bootpd.plist /etc
You will need to know the administrator password. If you do not have one set up, then you might need to set one up first. You will be warned that this could be dangerous. I don't know what any of this is doing, but it worked. So if it messed up my computer, I can't tell because everything seems to be working perfectly.
Okay. After you enter the password, hit the Return key.
Turn Internet Sharing back on.
Now. Go over to your PS3 and set up a wireless connection the "easy" way. I myself did not put in a pw for the WEP on my hotspot. So i did not need to connect using one. I suggest you do, and if it dosent work, just don't use one and it should work fine!
Enjoy your PS3 at any ethernet equipped hotel!