I've noticed many people find this "feature" very frustrating, although I personally don't have a problem, I've edited the dialpad flash file to
disable the screen-lock when your in a call AND when the keypad is on.
I realize there are some of you that want to just extend the delay period, but I haven't analyzed the file that much so this is all I can provide you with as of now.
Instructions:
1. Download the modified T1_dialPad.swf file at the bottom of this post.
2. Connect your phone to BitPim/EFS (If you don't know what it is, take a look at the Downloads/FAQ for more details on where to get it/how to use it).
3. Navigate to LGAPP > Media > Flash.
4. Back-up your T1_dialPad.swf file.
5. Delete the T1_dialPad.swf file on your phone.
6. Copy over the modified T1_dialPad.swf file (the one you downloaded)
7. Restart your phone.
Edit: An improved version of this has been included in the Extended Interface Package, see thread for details: http://www.lg-vu.com/index.php?topic=2057.0