restrict field update using current user as criteria?

[zestygirl]

I have a workgroup set up with users.

I have a form for updating projects which contains records for all users.

One of the fields is "Project complete"?

I want this record to be editable/updatable only for those that the current user is the project owner of. I want the field to be 'locked' (viewable only) for all other records.

I have a field called project owner that also appears on the form. So - if I am john smith, and record 1 has a project owner of Mary Jones, I should not be able to edit the field titled "Project Complete"? record 2 however, has a project owner of John Smith, so I should be able to edit/update this field (for my own records).

How does one go about assigning "owners" to certain records?
How does one include "current username" as a criteria when designing certain form features/query features?

for example, I may also want a command button on the switchboard that says "Show me my records" which brings up all records for the current user based on the username matching the record owner.

I know how to set permissions for ENTIRE forms/tables etc, what I have not figured out is how to set permissions for specific fields during specific instances, or permissions for currently logged in users.

Any help would be appreciated. I am not literate in Visual Basic, so, if your answer includes code - you may have to dumb it down a little.....