My <a href="http://www.bell-labs.com/project/TMP/">TMP</a> optimized
translator from (an extension of) LTL to B&uuml;chi automata is still available
for non-commercial use from Bell Labs. </b>
Please also see the excellent <a href="http://www.ti.informatik.uni-kiel.de/~fritz/ABA-Simulation/ltl.cgi">
LTL translation web page by Carsten Fritz</a> at Kiel U., where
TMP and Carsten's own more recent translator, as well as a number of other 
recent
optimized LTL translators, can  be compared via a nice online interface.