If you want to stream videos to your Playstation 3 from your computer it’s always best to have a wired connection whenever possible. If wired is not an option than having a good wireless connection is the next best thing. Wireless G is good for streaming standard content but if you want to stream hi-def content it might be better to upgrade to Wireless N router.
There are a lot of factors that can affect how well your wireless can stream videos to your PS3. Such as other traffic on your network, how far away you are from the wireless router, and obstacles like walls. If you are streaming low resolution videos like 640×480 a regular wireless g router should work pretty good, but for higher resolution content such as HD a wireless N router might be a better choice.
I am able to stream standard video (non-high def) with my wireless g router to my Playstation 3 without any problems, my wireless g router is about 15 feet away form my PS3 without any obstacles interfering with the signal.
If you are looking for some free software to stream video to the PS3 check out this article on PS3 media sharing.
Last I checked, PS3 didin’t support Wireless N, only Wireless G so having a Wireless N router wouldn’t make any difference. But, thanks for the info anyway.