After Jennifer Russel mentioned the New York Institute of Photography I did some more research where to learn more about photography. While the New York Institute of Photography does seem to provide a good training and to be recommendable, it also seems as some of the training material is outdated. So I looked around and asked in forums about other opportunities.
I was recommended to take a look at Moguefile.com, they provide a free online photography course by Jodie Custon who won several awards for her photography: Click here. My first impression was wow! In this course is a lot of information in ten short lessons. The course was written in 2004 but people still discuss the course in the forum of this site.
Then I can recommend the digital Photography School. There you can find a lot of great tips. I have just read one article about group shots and I really like it. This definitely is a source I will attend more often.
I also found a link to this site Strobist
This is a quote of the website:"This website is about one thing: Teaching you how to use your small flashes, off camera, to get professional results."
I hope this post is helpful!
Happy learning :-)
P.S. Not to forget one great place to learn about photography is microstock. I learned a lot by just being a contributer to microstock and submitting images and looking at which images are successful and which are not.