Revised 7/17/06: Four versions of this script now exist, and each might be useful to you depending on your set-up and need for features.

1. Script 3187: Basic Script for Firefox 1.5 and GreaseMonkey 0.6.4
2. Script 1240: Basic Script for earlier versions of Firefox and Greasemonkey
3. Script 2182: Deluxe Script by Johan Sundstrom w/ additional features
4. Script 4712: Combination of Johan's Deluxe Script & Singpolyma's Trackback Script.
   

For scripts 1 & 2, see my original how-to. For script 3, read on here. Script 4 is introduced on the Singpolyma Tech Blog:

What is Greasemonkey?

Greasemonkey is a Firefox extension that allows you to modify existing web pages with open-source user scripts, adding features & functions that will make your browsing easier.

So how does this make it easier for me to tag my posts?

1. Use the Mozilla Firefox web browser (v.1.5)
2. Install the Greasemonkey Extension (version 0.6.4, compatible with Firefox 1.5) Install instructions for Greasemonkey can be found at A Consuming Experience:

   To use Greasemonkey you have to first install that extension from the Greasemonkey site (Firefox users should be familiar with how - click the Greasemonkey extension link, if nothing happens and you see just below your tabs a message in horizontal bar that "To protect your computer, Firefox prevented this site (greasemonkey.mozdev.org) from installing software on your computer", you should click "Edit Options" at the end, then "Allow" and "OK" to allow that site to install software, then try clicking the Greasemonkey extension link again, give it a few seconds then click "Install now". Close and re-launch Firefox.)

3. Install Johan's Tag, Bookmark & Ping Script from Userscripts.org. View the text of the script in your browser, then go to the tools menu, & select "install this user script." For instructions & screenshots re: how to install a script, see greasemonkey.mozdev.org.
   
4. Head to blogger, & in settings > formatting, set "show link field" to "yes." This will allow you to see the extra compose fields that are added by the script.
5. Write a post.
   
6. Add your tags to the tags field, space or comma separated (great touch, Johan...)
   
7. This script does not require editing. The first time you select "publish" it will ask you a series of questions about how to format your tags.
   
1. What text do you want to precede / introduce your tags? (Filed in:, for example)
2. Tags that you'd like to add to all your posts (an "anchor tag", blog or author name, for example)
   
3. What page on del.icio.us would you like the tags to point to? (your top-level account page, or an account+tag+tag page, for example)
8. In the event that you make an error with these inputs, or want to reset them without reinstalling the script, you can click on the subtitle that introduces the tags field, which I have artfully highlighted with a red arrow below:
   

9. Publish your post. Note that you will need to be in the edit html side of the compose window when you publish. The tags will add to the end of the post, & will point to the location that you specified on del.icio.us.
10. In a great feature, Johan has also used this script to add a "post to del.icio.us" link to the publish notification page on blogger, which will pop-up a del.icio.us window auto-populated with permalink, title, timestamp & tags. Just hit "bookmark" over there & you're all set!!
11. You can also ping several services from the same notification window to let them know that you've updated. (Beware of ping spam, though, if you have blogger set to ping weblogs.com, or if you run your feed through feedburner & have turned on their pinging service, this step may be unnecessary...) For instructions on how to configure the ping options on this script, see Johan's post on pinging.
12. These tags contain the rel="tag" attribute, so they're also valid on technorati & other tag search services, & your posts should be indexed there automatically, once they crawl your site. Technorati tags don't have to link to technorati. They can link to del.icio.us and technorati will find them because of the rel: tag attribute.

See the two posts at Ecmanaut that explain the features and functions of this script. Blogger Del.icio.us Categoriser Script and Blogger Publish, Ping & Categoriser Tool. All good stuff. Integrated tagging for categories in the newest version of Firefox. Thanks, Johan!!

Update: To format tags on one line, instead of in a list, see Ecmanaut, where there are two sets of css for your template head. One puts the list on one line, & the second adds del.icio.us icons as your tag bullets. Very cool.

Update 3/1/06: The script has been updated to allow tagging inside the new RTF-powered blogger blogthis! Thanks, Johan!!