Locking a column & some other questions

Locking a column & some other questions

Hello,

I hope you can help me with a couple of things:
1. I would like to be able to lock one of my columns from being edited by any user that is not an admin. Is there a way to make a field not editable?
2.Also i would like to add a progress field where an user can update the progress of a project and keep the thread of the progress.
3. Is there a way to have multiple contacts under one account without duplicatiing the "account name"?
4. Is there a way to edit the ID field? Currently if I go to column properties there is an ID field, however when I activate it, a large number appears. Can I customize this to start from a preset number (i.e - 1001, 1002, 1003 etc)

Thanks for creating such an easy-to-use and powerful program.
Are there any programming languages I should learn so that I can write better scripts?