Hi,
Here are some (easy) pages about subject-verb inversion:
http://www.testmagic.com/grammar/explanations/inversion.htm
http://esl.about.com/od/advancedgrammar/a/inversion.htm
http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv34.shtml
http://www.edufind.com/english/grammar/ADVERBS7.cfm (at the very bottom of the page)
http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv342.shtml
http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv166.shtml
http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/1535_questionanswer/page61.shtml
Here is something more difficult:
http://www.bartleby.com/116/303.html