Regarding grammar books. I can recommend one small book that will answer most of your questions: The Plain English Guide by Martin Cutts, about $19. Also:

  • Writing, Researching, Communicating by K Windschuttle, E Elliott
  • The Elements of Style by W Strunk, E B White
  • Style Manual for Authors, Editors and Printers put out by the Australian Government Publishing Service, Canberra

On the internet just type in "grammar" and you'll be inundated with sources of free information. But the Martin Cutts book is excellent. My brother bought 100 copies and gives one to every new employee in his PR company and sends them to job applicants who write him grammatically incorrect letters (serves 'em right!).