Bitcoin Address Utility is an open-source program I maintain which does a variety of things. In general, whenever I write a Bitcoin-related utility, I tend to add it to this program, so it has become a “Swiss army knife” hodgepodge of various things I have created. This program runs natively under Windows, but because it was written in C# it will also run under Linux and Mac OS using Mono, a free software tool that allows C# / .NET programs to run without Windows.
The source code can be found on github at https://github.com/casascius/Bitcoin-Address-Utility
The binary can be downloaded from my website at https://casascius.com/btcaddress-alpha.zip (this file also includes the source code from which it was built).
Functions include:
- A calculator that lets you convert between private and public keys, hex and base58, bitcoin and altcoin addresses, etc.
- Bulk Bitcoin address generator
- Paper wallet printer
- Decrypter for encrypted private keys
- Self-escrow utility
- Intermediate code generator (used for creating encrypted paper wallets)
- Physical bitcoin insert printer (the small round private key paper found in Casascius Coins)
Announcements on Bitcointalk I have made related to this utility:
- Bitcoin Address Utility I made (July 2011)
- Passphrase-protected private key format BIP proposal (November 2012)
- Do-it-yourself Escrow with two-factor address utility (December 2012)
- Publicly released some of the magic potion that goes into physical bitcoins (December 2012)
casascius 
Is there a bitcointalk thread where you describe how to use the escrow tool part of btcaddress? It would be useful to have a canonical post to point people at.
The “Do-it-yourself Escrow with two-factor address utility” (December 2012) post talks about a passphrase, which isn’t part of the current scheme it seems.
Also, is there somewhere where you describe exactly how you generate the various codes? I’m thinking it would be useful to reimplement the same scheme in something that doesn’t rely on Microsoft code.
The tool itself opens up to a descriptive help screen when you open the escrow screen. No passphrase is involved unless you’re making two-factor paper wallets (not necessarily related to escrow, but people have managed to use it for this purpose anyway). I notice somebody else has implemented my escrow system in the browser and offered it up at http://bitescrow.org.