Where can I find a list of English paronyms?

After some more searching, I found this Index of Commonly Confused Words over at About.com. It's not perfect, but it's a good start.

Also, as has been mentioned on meta, there are at least two books on the subject: "Who's Whose: A No-Nonsense Guide to Easily Confused Words" by Philip Gooden and "NTC's Super-Mini Dictionary of Easily Confused Words" by Deborah K. Williams. I am not in a position to recommend or dismiss either, but I am listing them for the sake of completeness.

Lastly, as has been pointed out in the other answer, one day we will probably have our very own comprehensive list of questions tagged "look-alikes" or "paronyms".

Edit: yet another great resource (courtesy of VonC) is the online book "Common Errors in English Usage".

You can find a partial list by looking under the "look-alike" tag on this site:

https://english.stackexchange.com/questions/tagged/look-alikes

As the site grows, the list may become more complete.

If you google for "similar words in English" you get a lot of websites. alphadictionary has a list of 250 similar words.

http://www.alphadictionary.com/articles/confused_words_english.html