Caliber is a good freeware eBook reader and converter. With Caliber you can read eBooks and convert any document in eBook format.
The program supports various formats:
You can get LRF, PDF, LIT, RTF, OPF, Mobi, PRC, Epub, FB2, IMP, RB and HTML. You can export Mobi, LRF and Epub. The second iPhone reader is powered by Stanza.