Also, thanks to zhuhang for including this in his CM7 ICS / Jelly bean look and All in One ICS patch thread
UPDATE: You can now choose between ICS blue/ white style colours or the default green/ red colours for the lock rings, etc., I have attached different the applicable zips ("Lockscreen Icons ICS Blue.zip" and "Lockscreen Icons Default.zip")
This is my first attempt at doing some DIY themeing, this is very simple and did not take very long to do. Before I say anything else, bear in mind you must have root, and I am not responsible if your device is bricked, set alight or abducted by aliens due to this tutorial.
Screenshots are attached
On the G1, by installing CM7 it is possible to end up with a very nice ICS looking UI. You can do this through applying AChep's ICS theme, installing the Roboto font from ICS using an app such as Type Fresh from Pixelpod INTERNATIONAL and finally from finding ports of actual ICS apps, such as Holo Launcher by Mobint.
There is one problem though, which is that the lock screen is untouchable by themes such as Sonny Sekhon's.
And so we realize that we must theme it ourselves!
The actual lockscreen itself shouldn't be a problem, as CM7 has the option to use a holo style lock ring and to be set to "minimal", and once you have installed the ICS clock font for Clockopia (note that this isn't Roboto) found here (it's in the FontPack-Roboto_E2.zip file), you have a pretty clean looking ICS lock screen (See first attachment). Note I have also set the clock, etc. to be on the right side of the screen.
Now that that's done, onto the pattern lock .
So, I don't particularly like the Gingerbread pattern lock anyway, and it looks especially horrible when everything around it is nice and ICS-y.
I found a page here which is a tutorial on how to change the look of the pattern lock, but the icons are the wrong colour and the wrong size, and some icons are missing.
For that reason, I've done the "hard" work for you , so on to the tutorial ---->
Firstly, make a nandroid backup, although there shouldn't be much risk involved with this.
The apps you will need are Ninjamorph and to make things easy, a good file explorer, I personally use Ghost Commander.
You are now ready! The steps are as follows...
1. Open up Ninjamorph, grant SU permissions. I think you need to select "Start Checks" first.
2. Select "New Project", and locate framework-res.apk, it will be under /system/framework/ .
3. Although it backs up automatically, enter your file browser, go to /mnt/sdcard/AndroidThemes/workspace/framework-resapk/res/drawable-mdpi and copy the following files to a safe location on your sdcard:
4. I have attached a zip file named "Lockscreen Icons.zip", in here you will find the icons to theme the pattern lock.
5. Unzip "Lockscreen Icons.zip", then copy the contents to /mnt/sdcard/AndroidThemes/workspace/framework-resapk/res/drawable-mdpi . Notice that the icon names are the same as the ones you backed up, and also the same size. If you feel the need to edit them, do not change the name or size and do not save them as anything other than png files.
6. Open up Ninjamorph and select "Start Checks" as usual (you may need to locate back to the main screen first).
7. Select "Finish Project", then select "framework-resapk".
8. It will ask you to verify, to which you say yes, then ask if you want to zipalign, to which you will say no, I repeat: Do NOT zipalign.
9. Blah blah blah, it will do it's thing, extract and recompile the apk.
10. Now you've just got to reboot! , then admire you're ICS style pattern lock .
I've attached some screenshots of the results, the first 3 are blue/ white theme (no interaction, interaction, wrong pattern) then default green/ red theme (no interaction, wrong pattern, interaction). Note that I have swapped btn_code_lock_default.png and btn_code_lock_touched.png as they were the wrong way round. It is too difficult to get a screenshot, but when the corretc pattern is drawn the small rings/ nodes open up (become "o"s instead of filled in circles) again.
I hope this has helped, please thank me if it has and happy theming .