Sharing wi fi

[#1]

I'd like to share my wireless bb with other people in the house but I've asked them not to download films and music. Obviously there's nothing I can do about porn, but somebody told me that there are only a few sites that people use to download films and music, and he reeled off a list of names. Does anyone think this is true, and if so, what are the sites I should block?

[#2]

The biggest issue with domain blocking is proxies. If you block say softbunniesliveinthetub.mx then your resourceful children/mates will find a proxy like terrabits.bv to download via. The trick is to use the firewall to block outbound traffic on all ports and then permit traffic on common ports like 25, 110, 80 and 443. This is not watertight by any means, but it's a start to take counter measures against those BitTorrent like sites - but you may find BBCi Player and iTunes get crushed too.
In reality, introduce your own fair use policy. Download too much and be disconnected!
Use the router's MAC Access Control List feature to implement this.

[#3]

Thank you Thunderclap for that reply, although it makes me feel like a wireless virgin. I don't think I will have a problem and I think everyone will be fair but I feel as though I should make it look as though I have some idea of what I am doing. So are you suggesting I impose the firewall and permit traffic on only the 4 ports you mention and on no others? I am surprised that such a simple measure would work. Would it restrict my own activities?

[#4]

Experts will always give you a list of the worse sites, many of which are blocked by schools. And most school kids will give you a list of the non-blocked proxy domains that can be used to avoid the school's firewall! Domain blocking is fine in theory. In theory.
Given how different people's internet needs are, maybe you might want to consider sub-letting your internet connection - for a fee - and have a no-restrictions policy? Rembering of course, that you are still responsible to PN for any their service abuses.
And as a PlusNet customer you DO have the luxury of being able to view your internet activities :
https://portal.plus.net/view_my_broadband_usage/index.php?link=mc_myaccount
On the list are headings of Peer-to-Peer (like file sharing including bitTorrent and BBCi player), Streaming (like internet radio and some UTube content), Gameing (like Doom, 2nd Life, etc) and FTP (old-skool downloads).
So without changing any router setting, you can monitor your PN connection for any abnormal spikes in traffic. And then find out who is abusing the link!
Seriously, if you are not trusting of others, why are you letting them on your wi-fi anyway?

[#5]

Blocking ports wont help as most of the software can be downloaded from a browser on port 80 so if you block that they cant surf the web. There are 1,000 of website offering films and software etc you cant block them all. All you could do is use a free proxy from
http://www.youngzsoft.net/
and recorded their usage and let them know its all logged if you ever got caught for down loading illegal stuff you could point them at the culprit