The additional software I talked about called "CoolReader" was not adopted for Kindle touch yet AFAIK. As Doomer said it is not a simple thing for a non-experienced person, while not an impossible thing also. Most people use sony and nook without installing this software and they are doing quite well using "Calibre" to convert books to any desired format.
Yes, exactly. I use Calibre to convert anything to ".mobi" on a PC and then I send it to my Kindle for reading.
The only thing which I like to point out for Kindle (Touch or Keyboard) is the possibility to use English-Russian dictionary without any modifications. While Sony PRS-T1 provides only English-English Oxford dictionary and I guess the same is for Nook.