The hassle comes with the Messaging feature, which leads a zombie existence.
Apparently you have to decrypt the drive before applying any major Software Updates, but on the forums people recommend to do it for ALL updates. You'll have to wait for the next version of SuperDuper, but CarbonCopåloner reportedly works. Time Machine works, though the TM drive needs separate encryption. Now my boot time has doubled (not a big deal since I've got an SSD), but after that I have not noticed any impact on performance and the system behaves as if PGP never encrypted the drive. It took a few hours to encrypt 400+GB in the background. Once I got around to encrypting my Snow Leopard startup disc I had to create a new passphrase.
It turned out all that was not even necessary for WDE. The installation wizard walked me through creating public & private keys for one or more e-mail addresses and then publishing the public key to their global directory. Having bought a Whole Disk Encryption licence I was led to download PGP Desktop. The latest version 10 supports Snow Leopard. The Whole Disk Encryption and Messaging are covered by separate licences, however you will get the whole PGP Desktop suite, but with either of the two disabled if you just by one or the other licence. If it fails to find any, the e-mail is sent in the clear over SSL. It automatically looks for recipient's public keys in the global directory. The other half of PGP Desktop seamlessly intercepts your e-mail client's traffic and encrypts/signs & decrypts/verifies your e-mails on the fly. PGP Whole Disk Encryption has its own boot loader that will ask for your passphrase before the system will even boot, making it immune to PRRAM resets like the firmware password.
PGP Desktop as a stand-alone application can encrypt whole hard drives, including boot disks, as well as allowing you to create encrypted zip archives and securely shredding files.
It was created by Philip Zimmermann in 1991 and is now owned by Symantec. PGP is often used for signing, encrypting and decrypting e-mails to increase the security of e-mail communications. Pretty Good Privacy (PGP) is a computer program that provides cryptographic privacy and authentication.