go to limewire options and use the option to filter out certain words. I found that by filtering out a mere 5 words it seems to get rid of most of that crap (probably over 95%). If you then want to look at adult porn use the Bitzi look up feature (right click on the file title to find this feature) and check that the file isn't mislabelled (assuming there's a bitzi entry) as sometimes idiots will deliberately retitle kiddy porn with adult titles.

If you have no desire to download even adult porn then as well as filtering by keywords click on the option to ignore adult material and then still use the bitzi feature if you're looking for other movies.

If you ever have a similar problem again then you could do a simple little thing - note the IP number and then use the browse feature to see what other files that IP number is sharing. If it looks like there is reason to be concerned with what you then find you could then consider reporting that IP address to the FBI or the IWF in the UK (who don't deal with P2P reports themselves but will pass then on to the anti-pedophile unit in London). Of course, sometimes the IP address begins 192.168, so it can be hard to locate the real IP number (as I believe they are addresses of users behind a router and not the real IP address).