Today I threw together a quick sketch of an idea I had a while ago.  Consider it something of a social commentary:

http://www.openprocessing.org/visuals/?visualID=15532

Actually the end result isn't that important - the intention was to try a couple of new things in Processing that I've done with other technologies; and to force myself to have to sign an applet...  I gave up the last time I looked into this and little wonder: it's a huge PitA; on Windows at least :/

This is no way intended as a criticism of Ira Greenberg's wiki article ; but from the perspective of someone less experienced (read: an idiot like me who has always avoided working on the command line whenever possible) I think it could do with some extra detail as follows (I'll follow the steps in the wiki):

1. Ditto...
   
2. On Windows for 'terminal program' read 'command prompt' (usually in Start menu > Accessories).  Now it may be that on a Mac; or with an additional Java installation or some system tweaking; or with a different 'terminal program' you can access the Java utilities direct from the applet folder (any suggestions are very welcome), but that wasn't my experience.  Instead I had to navigate to

            C:\Program Files (x86)\Java\jre6\bin
   

   to run the keytool utility.
   (It's also worth pointing out that I suspect that nowadays, outside of computer science courses, there are fewer and fewer people who are familiar with navigating via a command prompt.)
   
3. If I've understood correctly 'pKeyStore' is the name of a file that will be generated in the next step.  'p5geek' is a name the key will be associated with.  Note that when you run this command you'll be asked to enter some additional (but straightforward) details.
4. Obviously match the names you set in the previous step.
5. jarsigner didn't appear to come with the default installation of Java provided with Processing...  So I had to download and install the JDK and then in the command prompt navigate to the appropriate folder - on my system:

            C:\Program Files\Java\jdk1.6.0_22\bin

   Also because I wasn't running the utility from the applet folder I had to include the full path to the applet in the command:
   
     jarsigner -keystore pKeyStore C:\ [snip] \ processing \ Letters \ Letters03.jar p5geek
   
   Even then it didn't work first time: it couldn't find the keyStore generated at step 4. I copy/pasted it across to the JDK > bin folder, ran the command again and it finally worked and the applet will now run online.
   

I have to say that all felt like a bit of a struggle and I now feel rather guilty about glibly telling people they just need to sign their applet when they've asked why they can't get it working online.  Next time I'll run keytool from the JDK folder to avoid the need to copy/paste the keyStore file (or whatever it's called) across; but it still feels like there should be an easier way.  I found a reference to using a utility in Eclipse; but it would be great if there were a way to do it direct from Processing.  Is this feasible?  Perhaps not if jarsigner isn't included in the associated Java installation?

Obviously if I'm missing something that seems blindingly obvious; feel free to call me an idiot and let me know: that was partly my intention for writing this...  Maybe I really have just missed something obvious?