There has been published work looking at algebraic attacks against A5.1 (the GSM cipher for most people). Look at: http://www.springerlink.com/content/eu97gk8786h7tj25/ and obtain this paper for full details.

Essentially, A5.1 and other similar ciphers are immune to algebraic attacks because the irregular clocking introduces many non-linear terms, and the order of the terms grows very quickly.

There was work published 2-3 years ago on this also: so this is not really new.