I’ve had a GPG key since 2001 (laughing at my e-mail address at that time is allowed, but not encouraged). My current GPG key was created in 2004, and the keysize is 1024 bits. While not urgent, it is a good idea to upgrade to a safer key.
I followed the how-to by Ana Guerrero, and I created my new GPG key with ID 3073EEC0DE1CCC58. It is important to sign your new key with your old key. The old key will be revoked at some point in the future.
If you have a GPG key that is still 1024 bits, it might be good to create a new one in the near future. If you don’t have a GPG key yet, the best thing is probably to download Enigmail or another similar program, and start using it right now.