Take this advice with a grain of salt, dear readers, because I'm not sure how reliable it is. According to Examiner.com, a Target staffer has advised shoppers looking for the Jason Wu line to "check for returns and restock online". And to do that, they suggest "bookmarking the Jason Wu for Target page on Target.com – and place “Jason Wu for Target” in the search box (exactly like that, including the double quotes) on Target.com’s search box at the top right-hand side of the website."
Now I get bookmarking the page, but the search term seem redunant, as you're already in the Jason Wu section. In fact, I just tried this, and all it does when you search on this term is to refresh the same page.
They claim that searching the term "returns an easily searchable list of items that give up-to-the-second restock data, such as whether the item is 'out of stoc online” or 'available in stores' "... but honestly, I don't know how up-to-date this information actually is. Before heading to the last Target on my list yesterday, I checked that store's availability on some items, and when I got there the items were gone. Yes, they could have sold out in the 10 minutes it took me to get there, or they could be in the dressing room with other shoppers... or more likely, the online stocking information is only updated by Target once a day.
UPDATE: Do NOT trust Target's "in stock at store" finder! My sweetheart of a husband went to a store 20 miles away today to try to get me the cat tote (which Target's site was IN STOCK at that store) and not only didn't they have it, but a store clerk told him that their store never got any in the first place :-(