Pretty much I use auctioneer, and as stated above, it has that feature in the Appraiser tab.

Appraiser is a batch post feature.
Each item is listed on the left.
To use it, you need to click on the item on the left, and then in the option window check, Enable Batch Posting.
The default is market value, but you can choose a variety of pricing methods or a fixed price.
You can also check "Price Matching" which will price your item like similar items if it doesn't have data on the item you are listing.
I use both features enabled on my auctions.

It is annoying, in that you need to check the boxes the first time you list any item.
There are two slider bars that are worth checking when listing new items.
One is the maximum number of those items you will auction at once - typically if you auction a ton of them, only first few will sell and you've wasted the post price.
Also if you put up 10 of an item, someone will come an undercut you. If you put up 2, chances are better you'll sell before someone undercuts your remaining 7 items.
Plus even if undercut, you can re-undercut if you choose to.
The second slider is stack size. For glyphs, I sell with a stack size of 1. For quest items, sell them in the stack size that is needed for the quest.
*EDIT* It is also worth changing your auctions to 48 hours, for maximum exposer time and the least amount of re-listing headaches.

Once you have it set up once, alt click the batch post button.
This is an auction scan of only the items which you have enabled for batch posting.
It gets the current average prices, and adjusts your price accordingly.
It won't undercut more then (default 10%, mine is set to 5%) below market price, but will go below other listed prices if it can, without violating your maximum undercut value.
Once you're done scanning, alt+shift+control and click the Batch Post button.

It batch posts every item you have enabled.
You do not need to alt click Batch Post for current prices if you don't want to.