http://biz.yahoo.com/ibd/040113/general_1.html

The above article is about 6 companies who yesterday announced they will list their stock on NASDAQ as well as on the NYSE.

Will this be the trend of the future??? Will a company stock really benefit from a dual listing??? Or is this a way of nudging the NYSE to clean up their act???

It seems the trend hasn't really gone very far since those initial announcements, but it's still early to say if it will ultimately go anywhere:
http://quote.bloomberg.com/apps/news?pid=10000103&sid=aaDPnp2iDeXY&refer=us

The article above gives a little reasoning for it, but not much. The reasoning on Nasdaq's side is basically that they hope NYSE companies will dual list, decide that Nasdaq is better, and move to just Nasdaq. Companies are likely hoping that the increased competition will make both markets more favorable for them.