Here is a brief list of things that still need to be done.

More unit tests:
   - Implement more unit tests for block chain functionality
   - Create a MockNetworkConnection and use it to test the Peer.

Protocol:
   - Properly support multiple chains
   - Start up faster
      - Store a block locator in the wallet
      - Parse the stored headers at startup, then download the rest
   - Provide a seed node list in the NetworkParameters.
   - Implement tx fees.
   - Support import of private keys and then extracting its transactions from the block chain.
   - Longer term potentially add a getmerklebranch protocol command so we can check 0-confirmation transactions.

Examples/documentation:
   - Implement a simple Swing GUI payment app.

Cleanup:
   - Find a way to avoid some horrid hacks when shutting down the network connection.
   - Implement a BitCoin class that encapsulates a BigInteger and formatting.
   - Make NetworkParameters use subclasses instead of static methods to construct.