Rated 5 out of 5 stars

For Windows x64 Editions
(mine is Windows 7 x64 Enterprise) tested on WinXP x64 too

1. Install GPG4WIN
2. Install Enigmail
3. Restart Mozilla Thunderbird
4. Configure ENIGMAIL: Tools->AddOns->Enigmail->Options
Look the path to gpg.exe to be correct

PATH to GPG.EXE on x64 Editions

PATH to GPG.EXE on x86 Editions

5. Restart Mozilla Thunderbird
6. On Menu bar look for OpenPGP click and start Setup Wizard
7. Generate key of your flavour ;)
8. Menu->OpenPGP->Key Management->RIGHT CLICK SOMEWHERE and look for this:
Upload Public Keys to Keyserver
After choose keyserver to upload (personally I upload public keys to all available keyservers) each.
9. Double click on your key and copy exactly the Key ID
10. Click on keyservers->Search for keys and PASTE your Key ID
You'll receive OpenPGP Alert with data of your key if you correct made step by step guide above.
If you need more help and how-to work with it, please read here:

This review is for a previous version of the add-on (1.1.2).