rar is an archive format similar to zip

get 7-zip (i don't have enough posts to give you a link yet)

and i use bonkenc to convert

google for them. both are the first link on my google searches

oR Winrar.
Whichever you find first.

winrar is good. but i suggested 7-zip as it is a free open source software over the shareware winrar

free beats paid app almost any day of the week