^^Agree with Ladyisobel - Bonanzle is a great place to get started. The thing is is that it's slower than Ebay to sell, dependent on the item. If you do want to try Ebay, start off with a few smaller items to build some feedback for selling - as much as feedback is skewed these days (in that sellers can't leave negatives for buyers any more), it is still important for a lot of people, especially when buying high end goods.
Whenever you list a bag, always take good, clear photos, preferably in natural daylight and of all the key points - stamps, date codes/serial numbers, engravings e.t.c and direct potential buyers to the "Authenticate this LV" thread for an unbiased opinion on authenticity. If you are listing on Ebay, there are a good many things to be aware of - attach a security tag with your username on it (Tyvek wristband) to anything you send out - it's not foolproof but it does help to avoid bait and switch scams e.t.c
Be accurate in your description of flaws/usage, don't try to avoid any problems no matter how small because these things will come back to bite you. Always pay attention to the Paypal page of the transaction to make sure you are eligible for seller protection and send to the address on this page.
There are many, many threads on this forum with lots of advice and info - be aware there are lots of threads to do with scams but there are plenty of good transactions that occur on Ebay - it's just a bit of a minefield these days so you do have to be careful. That being said, it is the same for any online transaction.
If it all seems a bit scary then you can consign, but do be aware that they usually take quite a high comission and you will still pay listing fees e.t.c so it depends how badly you want the money. Bonanzle like i said, is probably the better place to start. You can vet your buyers and set up your auction (it's not really an auction site) so that people can't buy the item straight away without contacting you first e.t.c which is really handy.
I've sold quite a few things on Ebay with no problems, but i'm awaiting a couple of things at the moment to be received and i'm waiting with baited breath, praying there won't be a problem - these days, Ebay sellers are treated like department stores so you basically have to cross your fingers and hope....