Lindsay Lohan -- I'm Signing On to Become Liz Taylor

Lindsay Lohan is ready to sign on to play Liz Taylor, and she's going to complete her community service faster than required to clear the decks for shooting the flick.

Lindsay -- who will appear in court at 10 AM PT for her probation progress hearing -- is in the final stages of negotiating the deal -- this according to sources very close to the actress/perpetual defendant. We're told the plan is to sign the deal early next week.

And we're told ... Lindsay is actually getting more scripts than she's received in years -- apparently producers have noticed she's finally showing some maturity.

As for today ... as we first reported Lindsay has completed the required morgue work and psychotherapy sessions. If all goes well, she'll be off probation at the end of March.