I really haven't heard of being both Christian and Wiccan. It's too confusing and impossible to accomplish, in my opinion. I understand you still have those Christian ideas, such as Heaven and Hell. Just because you're not Christian, doesn't mean you have to give up those ideals. Granted, you could tweak them to fit your true ideals.
As a former Christian myself, I never abandoned ALL of the beliefs from the Bible since they are similar to some Wiccan ideals. Commandments 6-10 are generally anything you can still believe, even if you're not Christian. They're common sense, since you are aware of the consequences if you break them, spiritual and legal. Although I believe the first one is a little selfish and conceited, I bear no real grudge against Jesus Christ. A Christian can still practice magick. A Wiccan can still read the Bible. There's no such thing as a "True Christian" or "True Wiccan." Whichever you choose, you can still have most or all the ideals you're used to. Just remember, converting is never easy. You may end up giving them up and letting new ones in. If you're prepared, then there shouldn't be too much problems.