As announced in the AdWords blog on March 15th 2011, Google will be removing the managed placements default bid. If you are targeting managed placements this will affect you.
Currently on managed placement targeted campaigns, you have three bidding options: Default Maximum CPC, Managed Placements Maximum CPC, and Display Network Maximum CPC.
Google are gradually introducing this change, however by March 15th they will be updating your existing managed placement bids. How exactly they plan on updating the bids will be interesting to see, especially if you have a separate bids for each bidding option.
It also appears that a new AdWords Editor will be released to deal with this change.