You have to unpack the rar files, there probably named r01, r02, r03 etc
once you unpack them you should have a .ipa file. you then add that file to itunes and the add to your iphone/ipod touch. im asuming that your iphone is jailbroke.
Forgive me if thats not explained the best i only jailbroke my iphone on sunday and have had to read a lot of stuff myself the last couple a days
Can't you install installous and have your apps installed that way instead of sshing? I get a lot of invalid ipa but I clearly meet the requirement someone mentioned installing it manually so is that what you are doing???