fplll does LLL-reduction on lattices. It is written by Damien Stehlé, David Cadé and myself.
LatEnum is a program and a library which solves the Shortest Vector Problem (SVP) and the Closest Vector Problem (CVP) on integer lattices, using floating-point arithmetic. The source code (except the parallel version) is now included in fplll, but you can still download the standalone version.