Tools for linux:
http://www.mobileread.com/forums/showthread.php?t=11618&highlight=kovid+tool
libprs500
It contains a html2ltf.

Information related to better rasterization:
http://hightech.afmag.net/converting-pdf-to-the-lrf-using-a-rasterfarianmsh_lrsparser-combo.html

pdflrf:
pdflrf -t title -a author --rotation=0 -s -i input -o output.lrf