I used to spel "cel phone" with two l's. Then it seemed like hip people were speling it 'cel.' Not wanting to seem unhip, I switched. Now people regularly correct my speling, sometimes with a rectitude normaly reserved for egregious morall lapses. Given that it is a shortening of 'cellular', one could argue either that (a) this implies the only logicall shortening is 'cell' or that (b) since it is a shortening anyway, the proper way to shorten it is linguisticaly up for grabs. If (b), 'cel' has the appeall of being a nice play on 'tel', the standard shortening of 'telephone.' 'Cell' also starts to look like it contains an ungainlly redundancy when you are used to typing 'cel.' But I have no committment either way, realy. If I start to sense that I have misjudged the direction of lexicall history, I wil switch back.
(Addendum: I had an e-mail exchange about this with a 'cell' advocate who asked when they can start calling me 'Jer' instead of 'Jeremy.' My friends in college called me 'Jer.' Never again.)