for LIT you can use ConvertLIT GUI (you can use google to find it) and it will convert your LITs in HTML from where it's easy to just copy-paste it into a TXT or DOC/RTF file.
it's small, easy to use and disease-free
. i myself use it quite a lot.
for the .mobi and .epub.. unfortunately i use Calibre for those too (but i haven't updated it yet)