Well, I'll get straight to the point. This tweak will allow you to change the default icon for the e-mail shortcut in the start menu to whatever you want. You should be familliar with regedit prior to trying this.
1. Click on "Start" and go to "run"
2. In the run dialog type "regedit"
3. Go to "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\" by expanding the appropriate branches of the tree.
4. Select the email client that you are currently using.
5. You can now modify the (default) key and rename the shortcut to whatever you want.
6. To change the icon expand the selected client and click on "DefaultIcon".
7. Change the (default) key to point to the icon file of your choice by double-clicking it. If you are going to use a .exe file with multiple icons inside you should specify with a comma after the target the index number. (Eg. C:\icons.exe, 2)
8. Reboot your computer for the changes to take effect.
That's it! Have fun.
P.S. There probably is another section to change the shortcut name & icon of the internet client but I was too lazy to find it.