When I am doing online research for a school paper how can I be sure that the internet sites and search engines that I use are giving me reliable, up to date information?

Cross reference.
Don't rely on one soucre and NEVER quote wikirel

You can't trust any internet sourse for sure, If for example you are on the actual Catholic Church web site then you know it is normally right, but if you are on a local independent church and they link to their pages on the Catholic Church there is a good chance they are not correct

So if you want info on the IRS, only use official .gov web sites

And as noted by Curlyben that online information sourse that some of us quote for this site, is merely cut and pasted by people that offer the info and has a lot, ( I mean alot) of poor info.

General searches I like Google but if I was a student I think a lot of time ask.com and answer.com are better. -- Savage

It does depend largely on the site and the topic you are researching.