There are many informative websites ( as well as the usual trash) for those seriously interested in finding out more. From the tenor of most of the postings here so far though, I doubt that many will pursue them.
For those already involved, the main problem in discussing Wicca with non pagans is where to start! (For example, in the US the term is applied very broadly - and increasingly so in the UK too. Originally - and strictly speaking - it refers to a tradition of practices developed since the early 1950s, but based upon and drawing inspiration from pre-Christian spirituality.)
I have many Pagan and non-Pagan friends and I respond to them all on the basis of what they do and say, not on their belief systems - which are entirely a matter for them.