There was a fair amount of interest for my recent post about spinoffs.
An excellent resource for recent and upcoming spinoffs is StockSpinoffs: http://www.stockspinoffs.com/recent-spinoffs/
The recent ones look a little out-date, but it is still a site that is maintained actively.
You can search Edgar, the US Securities and Exchange Commission, for 10-12B(/A) forms:
http://www.sec.gov/cgi-bin/srch-edgar?text=form-type+%3D+10-12b+OR+form-type%3D10-12b%2Fa&first=2015&last=2015 (equivalently: http://is.gd/WaqOgb)
Form 10-12B is a registration statement that companies must file when they issue new stock in a spinoff. Sometimes information is missing, like the date of the spinoff. Forms 10-12B/A are ammendments to forms, which may fill in some of the blanks.
One last tip: you may want to copy the RSS Feed link into whatever software you use for reading feeds. That way, you can stay up-tp-date with the latest developments.
All resources listed in this article are free.