Without more details of the bottles that you are considering selling, it is difficult to offer any meaningful advice as to a valuation. Thre are a number of private bottlings currently for sale on http://whiskyauction.com/
, although you should note the commission that is charged. Similarly you could try selling the bottles through McTears. The obvious way to sell is via ebay, although they only allow the sale of the bottle if the contents can be deemed as being coincidental. It might be worth posting photographs of the bottles on here as they are a number of users who will have a fair idea. It might also be worth enjoying a couple - they're not going to go off and the best way to dispose of any whisky is by recycling it through the human body. Good luck.