sen247 says:
can you recommend one, because I have never read anything by him.

Sumner says:
"The Call of Cthulhu" may be his most famous. I have also read "Nyarlathotep" and found it enjoyable. I have to limit my dosage of Lovecraft though, due to sometimes disturbing dreams.... ;-)

cresswga says:
There was a post about Lovecraft in the horror forum a while ago.

http://www.dailylit.com/forums/tag/133/181

There appears to be a question mark over whether the books are actually in the public domain at the moment but a lot (if not all) of his short stories can actually be found here:

http://www.gutenberg.net.au/ebooks06/0600031h.html