Q: What is GPG?
A:GnuPG is a complete and free replacement for PGP. Because it does not use IDEA or RSA it can be used without any restrictions. GnuPG is an RFC2440 (OpenPGP) compliant application.

Q: What is PGP?
A: PGP stands for Pretty Good Privacy, a freely (at least for private use) available program from Phil Zimmerman for public cryptography, thus serving your privacy.

Q: What is public cryptography good for?
A: You can easily send/receive encrypted messages (e.g. e-Mail) to/from people who have a PGP key and so you can be sure that no other person can read the contents of this message. You also can make digital signatures to any data that proof their integrity and origin.

Q: From where can I get public keys of people?
A: From Public Key-Servers (click here).

Q: How can I be sure that I got the acutal key of that particular person?
A: Public Keys are often signed by other people (with their public keys) who know the individual personally and confirm this way that the key really belongs to this particular person.