lzip is a lossless data compression program which can be used with tar for compressing archives. It supports to variants of the LZMA algorithm, one really fast and one normal used by all compression levels except 0. It's lowest compression is as fast as gzip with better compression and it's highest compression level is better than bzip2. It is designed to be a replacement for both bzip and gzip.
There are two versions of lzip available, lzip and the multi-threaded version called plzip. Most distributions have lzip in their repositories. Compressing with lzip horribly slow compared to both plzip and other algorithms - compressing the Linux kernel takes 1 minutes with plzip and 5with standard lzip.
plzip's performance is about the same as xz's parallel implementation pixz.
See Comparison of Compression Algorithms for more details.