Ebay seem to have recently introduced software to prevent buyers and sellers from exchanging e-mail addresses (and probably also telephone numbers although I haven't tried that) via the Ebay e-mail system.
However, one buyer I've been corresponding with has found a way round this, and that is to send a photograph of the e-mail address. In my case, being photographically-challenged (those of you who have met me would probably correct that to photogenicly-challenged

), I used the textbox function in Paint and saved the result as a jpeg. I was then able to forward my e-mail address to the seller without any problems.