Where were the Dwarves?
 

I know Gimli arived in Rivendell with a company of Dwarves but where were the Dwarves when the battle for Middle earth was happening?

The Battle of Dale and Erebor. Read about it in the appendices at the end of Return of the King.

Hullo! First of all, welcome to the Downs.
As far as your question goes, if you see the appendices of RotK, you'll see that the Dwarves were fighting the battles of Dale and Erebor.

Thank you for the welcome :) and thankyou for the info i just read that sauron sent a host of easterlings and were met by dain

Now, I am positive that there is a chapter in the Return of the King in which Gandalf explains to the hobbits, and I think Gimli, what happened at Erebor while the battle at Pelennor Fields was happening. I am also sure that there was something in the Unfinished Tales that mentioned it. But now that I've gone to find them, I cannot. :o

Anyway, welcome to the 'Downs, Gandalf! I hope your stay is long and comfortable.

At the moment, I can't recall anything regarding the events at Erebor being detailed in LOTR, other than in the appendices.

The UT chapter touching on it is The Quest of Erebor. There, part of the narrative is ostensibly taken from writings made by Frodo in Minas Tirith as he listened to Gandalf explain why he wanted Smaug out of the way, and also spoke of the Battle of Dale. Perhaps that's what you had in mind.

Ah, that probably is what I was thinking of. No wonder I couldn't find it in LotR. *headdesk*