ICE stands for Information Concealment Engine. It is a 64-bit private key block cipher, in the tradition of DES. However, unlike DES, it was designed to be secure against differential and linear cryptanalysis, and has no key complementation weaknesses or weak keys. In addition, its key size can be any multiple of 64 bits, whereas the DES key is limited to 56 bits.
The ICE algorithm is public domain, and source code can be downloaded from this page. There are no patents or copyrights, so its use is unrestricted. Naturally, if you do decide to use it, the author would love to hear about it.