Grand Theft Auto III/Walkthrough

Story Missions
Introduction
 * 'Give Me Liberty'

Luigi Goterelli
 * 'Luigi's Girls'
 * 'Don't SPANK Ma Bitch Up'
 * 'Drive Misty For Me'
 * 'Pump-Action Pimp'
 * 'The Fuzz Ball'

Joey Leone
 * 'Mike Lips Last Lunch'
 * 'Farewell 'Chunky' Lee Chong'
 * 'Van Heist'
 * 'Cipriani's Chauffer'
 * 'Dead Skunk In The Trunk'
 * 'The Getaway'

Toni Cipriani
 * 'Taking Out The Laundry'
 * 'The Pick-Up'
 * 'Salvatore's Called A Meeting'
 * 'Triads And Tribulations'
 * 'Blow Fish'

Salvatore Leone
 * 'Chaperone'
 * 'Cutting The Grass'
 * 'Bomb Da Base'
 * 'Last Requests'

Side Missions
Marty Chonks
 * 'The Crook'
 * 'The Thieves'
 * 'The Wife'
 * 'Her Lover'

El Burro
 * not done yet

Staunton Island
Asuka Kasen
 * 'Sayonara Salvatore'
 * 'Under Surveillance'
 * 'Paparazzi Purge'
 * 'Payday For Ray'
 * 'Two-Faced Tanner'
 * 'Bait'
 * 'Espresso-2-Go!'
 * 'S.A.M.'

Kenji Kasen
 * 'Kanbu Bust Out'
 * 'Grand Theft Auto'
 * 'Deal Steal'
 * 'Shima'
 * 'Smack Down'

Ray Machowski
 * 'Silence The Sneak'
 * 'Arms Shortage'
 * 'Evidence Dash'
 * 'Gone Fishing'
 * 'Plaster Blaster'
 * 'Marked Man'

Donald Love
 * 'Liberator'
 * 'Waka-Gashira Wipeout'
 * 'A Drop In The Ocean'
 * 'Grand Theft Aero'
 * 'Escort Service'
 * 'Decoy'
 * 'Love's Disappearance'

King Courtney
 * 'Bling-Bling Scramble'
 * others

(this list is incomplete)