AFAIK, the particular brew used by PGP (I think it's a combination of RSA for key exchange and long-key RC5 for the actual message encryption) is quite strong, to the point that "millions of years" is probably overestimating the processing power of modern computers by an order of magnitude or more. There is a known algorithm to break the basis of RSA (the difficulty of factoring products of extremely large primes and pseudoprimes), but as far as anyone's saying no hardware exists that can run it right now (it's a quantum algorithm; no ordinary computer can run it as it depends on influencing and analyzing quantum interactions). However according to experts in the field the same hardware that will enable breaking RSA will also enable a new form of encryption that won't be breakable by the same means.