What is FireGPG ? FireGPG is a
Firefox extension under MPL which brings an interface to encrypt, decrypt, sign or verify the signature of text in any web page using GnuPG.
Support for Gmail FireGPG adds some features to the
Gmail1 interface to let you use GPG's features directly in your webmail. More webmail applications will probably be supported in the future.
FireGPG is openpgp/mime compliant !
Check
webmails supported by FireGPG 
Inline detection FireGPG is able to detect PGP blocks in any page (for example a public key), and lets you easily manage these different blocks.
API FireGPG has an API that allows you to design a website that uses GPG's features on the client; for example to autheticate a user for an administration pane.
Translations FireGPG is currently translated into many languages. We encourage you to contribute; it's easy (see link on the left !)!
Interested ? Have a look at the screenshots's page or Download FireGPG ! FireGPG - use GPG easily in Firefox !