We're told she'll be processed there as soon as she arrives in the next hour or so -- meaning her fingerprints will be taken ... and they'll even take a brand new mug shot! According to the impeccably-researched TMZ Hollywood Bus Tour, that will be mug number 5. Tickets are on sale now.

Once that's complete -- Lindsay will post bail -- courtesy of her go-to bail bondsman -- and be released. She's due back in court on May 11 for her pretrial hearing.