Here's a simple schema to show what is meant by signing an application :

You need to have 3 things:
- An account at www.symbiansigned.com
- SignSIS Files
- DevCert Request Tool
To get an account at Symbian Signed you must have a non-public e-mail address (yahoo and hotmail do not work). If you dont have one, you can register for one at Web Site & Email Services. Then use this address to register yourself at symbiansigned.
Then you must have the SignSIS files (it is attached for you in the thread) and the DevCert Request Tool. to get the latter go to:
DevCert Request Tool. Install the tool on your PC.
Now the signing process starts:
Part One
1. Create a folder and put the unsigned sis file as well as the 2 SignSIS files in it.

2. Open the installed tool.
3. create an output in the same folder as your sis file ( I suggest you rename your sis file to something short and simple because this name will be used more than once in the process eg: abc.)

4. On next screen select 'private key file'. Then give the key file the same name as the sis file and put it into the same folder.

5. Put password 12345.

6. Fill the next screen with any data you want.

7. On next screen, insert your mobile IMEI.

8. Highlight all of the "Application Capabilities" and click Add. on next screen click finish.

Part Two
Note: you will see that new files have been created in the folder.

1. Go to symbiansigned and log on ( remember your username is your email add)

2. Click on th 'My Symbiansigned' tab and then on the 'Developer Certificates'. Click 'Request'. Enter the given code, browse for the .csr file in the folder and upload it.

3. When the uploading is over you'll get a .cer file to download. Save it in the same folder with all the other files.
Part Three
These are the files the folder will have now.

Now you will sign your file.
1. In the folder open the 'auto_signsis.bat' using MS Notepad.
2. Replace every xyz by your sis file's name.
e.g: signsis xyz.sis xyz_signed.sis xyz.cer xyz.key 12345 becomes signsis abc.sis abc_signed.sis abc.cer abc.key 12345 ( if abc is the name of your file.)
3. Click save, NOT SAVE AS.
4. Run the 'auto_signsis.bat'. You'll see that a new sis file will be generated. THIS IS YOUR SIGNED FILE! Enjoy it!
UPDATE on 13/11/2007:-
Altohugh I havent tried it myself, there are some who say that you can sign at symbiansigned with an AOL account. Try and inform me if it works.
UPDATE on 16/11/2007:-
Ok now you can use a new version of signSIS created by BINPDA. Using this one will ease the work as you wont need to do Part Three. Download the new signSIS_BINPDA.rar file that I have attached use the program, its simple and very easy.
UPDATE on 16/11/2007:-
Screenshots added for steps 1 to 3.
UPDATE on 23/11/2007:-
Schema picture added.
UPDATE on 26/11/2007:-
New working e-mail service found. Go to Meta Crawler Search Engine and get an email account.
UPDATE on 27/11/2007:-
New working e-mail service found. Go to MyBestMail :: Best free web based Pop3 email service! and get an email account.
Tutorial By : Vip_blast at noeman.org/gsm
DOWNLOAD :
http://rapidshare.com/files/73467565/BinpdasignSiS.zip