FireForm is a simple extension developed by Jean Marc Bastide to solve a common annoyance: filling out web forms.

Since most of registration forms ask for the same information: name, address, phone number, email address, date of birth; FireForm makes a best guess of what a specific field is asking for. 

You will first need to create a profile with all the information you want FireForm to fill automatically. Then, the next time you are presented a web form, just click on the status bar icon and detected fields will be automatically filled out. If you have more than one profile, for example for different shipping addresses or if sharing your computer with someone else, just right-click and select a profile.

Fields that are automatically filled out are highlighted so you can easily check if the correct information was provided. 

I tested it with eBay and amazon.com registration forms and it did a superb job.

By default it is configured to properly identify fields in English and French, but fortunately it comes with an Advanced profile management dialog where you can configure what field names you want to associate with a particular value. I configured my setup with Spanish field names and it completed the most part of some Spanish forms I tried.

A major weakness is that Fireform's profiles are stored in plain text instead of encrypted as supported by Firefox. The developer notes it very clearly in the profiles window and I hope this is improved in future versions.

If you are not much concerned about this, you may want to try this nifty extension that promises to save lots of time. You can try it at Mozilla Add-ons.