Theres 100s of 1000s of ebooks out there, the majority of them being total crap. So my question would be what are you going to do to make yours stand out above the rest? That should be your main focus right now.
You can find examples of ebooks in the download section here, check those out for ideas (ideas on what not to do lol!) these are the sort I was speaking about before, they are sold on WaFo for a few bucks a piece and they usually suck badly, but you can find some rare gems I have to admit.
Really if your going to do this, find something people really need help with and give them the solution. Price it well and create a good site to sell it, look at places like clickbank then to promote it if your going down the membership route.