I keep having to unplug my modem to get a connection

YES. the modem still has the info of the previous device which it only releases after it is rebooted.

use a router - which you should use anyway since it will add security to your internet connection - and connect both, computer and PS3, to it.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Agree, when i use to do that i had to reset my modem each time as well.

I would also suggest a router, that way you could either get another CAT5 cable and hard wire the PS3 into the router, or just use the built in Wi-Fi since you will be so close to the source. You have enough connection speed (download at least) that online gaming and streaming should be no problem using it wireless. Mine works fine from about 60-70 feet away from the router with a 30 down/5 up connection. The upload speed is really only important for games where people have to host the game using their connection for everyone in the room (for example Rainbow Six Vegas 2). Without good upload speeds you can never host a many people, and will pull other people's rooms down.

Dear Emerald and Steimy,
Thank you for the advice. I believe you guys are correct. My questions now are: I definitely do not want to cause an online game room to crash. My upload speed is around 2mbps or 3mbps...is that good/fast enough so that I will not 'drop' games or lag the rooms?
My other question is: What router is the best to buy for use with online gaming? And how do I determine the quality of the cable modem provided by my cable company? In other words... Do I also need to buy an upgraded modem along with a router? - plus another HDMI wire and some ethernet wire right? -
Anywho, thanks Toms

I like the linksys E2000 it tested as one of the fastest gaming routers.

just turn of your modem connect the router and then connect the two computers.

power up the modem and wait until it syncs. then turn on the router. log into the router and configure the wireless security or turn the wireless of if you do not need it.

the router should come with one network cable so make sure you have a network cable for each of the computers.

I personally like the Linksys WRT54G with speedboost. Used it for years with both my Xbox 360 and PS3 from about 70 feet away.
But it is old school so it doesn't have the new wireless N like what Emerald's suggestion should. But last time i checked the PS3 can only do wireless B & G so wireless N would make no difference for gaming.

If you want to hard wire into the router you would need 3 CAT5 ethernet cables
One from modem to router, one from router to computer, and one from router to PS3
But if you have at least 15 down and like 2 or 3 up as your speeds and are 60 feet or less away from the router i would just try the wireless unless you model doesn't have it for some reason (or you decide on a regular router rather than a wireless model). You should not have any problems gaming with those speeds or lagging in rooms.