There is a tricky thing about downloading PGP. For American visitors, they don't have any problems, just go to the PGP page. For the international users, there is an export restriction issue. The US of America have a crypto-export restriction. In short terms they say that you cannot export strong (whatever that means) cryptography from the US. In January of 2000 although, the restrictions were eased. So I'm not absolutely sure what the status of the restrictions is. However, the international visitors should go to PGPi in order to get their version.
To find out about the real newest version for your machine, go to the PGP Interactions Page. Here all the supported platforms are listed!
The following links are here just for completeness: