I hope this will help me figure out what's going on when and what side people are on. Please contribute and make corrections. The dates come from Lostpedia which is not canon, but is pretty close.
100 BC? - Days of the 4-Toed statue; Locke puts the Donkey Wheel back on its axis and turns it
1845 - Black Rock disappears. Magnus Hanso was captain of the Black Rock.
1954 - Richard Alpert and a band of Latin speaking Others including young Charles Widmore and Ellie are on Island and view it as THEIR Island
- US Army arrives on Island with 18 men and Jughead. 18 Army people die on orders from Alpert's superior.
- The Left Behinders (LBs) jump to 1954 and Locke, Sawyer, Juliet, Miles, Daniel and Charlotte plus 2 redshirts interact with Alpert's Others. Both Alpert and Ellie are told about the time skipping.
1970s - The Dharma Initiative (DI) funded by Alvar Hanso begins building stations on the Island. They create a station, The Arrow to deal with the hostile indigenous population presumably Alpert's Others.
1970 - Charlotte Staples Lewis born
1973 - Young Ben Linus joins the DI and arrives on Island with his dad.
- The Hostiles, presumably led by Alpert, attack DI facilities
- Young Ben sees his mom and in an effort to find her encounters Richard Alpert
1974 - Sawyer, Juliet, Jin, Miles, Daniel and presumably Rose, Bernard, Vincent and any other remaining 815ers end up here after Locke turns the wheel
Hostiles kill DI member Paul
Sawyer and Juliet kill 2 Hostiles and rescue DI Amy
Sawyer tells DI his name is LaFleur and he and his crew integrate into the Dharma Initiative after also informing Alpert what, that is who, they're waiting for
The Dharma submarine travels approximately every 2 weeks to and from the Island
- Daniel (not sure if it's 2005 or other aged Daniel) travels to the time they are building the Orchid. I'm thinking now this is definitely 2005 Daniel, but the exact date of this scene is unknown.
1977 - Sawyer, Miles and Jin work for Dharma security
Juliet works as a Dharma mechanic and only reveals herself to be a doctor in order to deliver Amy's baby
A baby is born to Amy and Horace; no word on where it was conceived.
Kate, Hurley and Jack are flashed into this time from Flight 316 and are found by Jin
Motor Pool Kate, Chef Hurley and Workman Jack are part of the DI
Sayid in DI custody as a presumed Hostile; visited by young Ben
Young Ben springs Sayid; Sayid shoots him in the jungle and flees
1980s - Alpert's Hostiles and Ben purge the DI with poison gas. Possibly 1984/5 if you take Miles statement that Widmore has been looking for the Island for 20 years as accurate. This date does not agree with Horace's dream statement to Locke though. At this point Island is left with just Alpert's Others plus Ben plus possibly other DI that become Others or are left to die at the hands of polar bears. We do not know of any DI escaping the Island post-purge, but somehow Daniel knew about the purge as evidenced by Daniel and Charlotte's trip to the Tempest. I suspect Widmore knew about it too, but I don't know chicken and egg style if he told Daniel or Daniel told him.
November 18, 1988 - Rousseau's team crashes on Island
- Rousseau goes to radio tower and changes message
- Ben takes Alex. Alex becomes an Other.
Post-Gulf War maybe 1991/2 - Kelvin Inman arrives at the Swan
- Mikhail arrives on Island about then too.
1995 - Desmond meets Penny
1995/6 - Desmond meets with Charles Widmore to ask about marrying Penny
Desmond sees Charlie Pace performing on a street in London
1996 - Desmond meets Daniel in Oxford
Charles Widmore buys Black Rock ledger from the Hanso family
1997/8 - Daniel sends Teresa time-tripping, leaves for America, Widmore pays for Teresa's care
Late 1990s? - Nigerian drug plane crashes on the Island
- Ethan checks out plane crash and shoots a 2005 Locke
- 2005 Locke sees crash and is shot by Ethan
2001 - Desmond meets Jack at stadium in LA
2001-2004 - Desmond lives in Swan Hatch
Sept. 22, 2004 - 815 crashes and Kelvin dies
Nov. 1, 2004 - Aaron born, delivered by Kate
- Time skipping LBs jump here from 1954 and see Swan lit up as Locke pounds on it and Aaron's birth
Nov. 2004 - Desmond meets Locke, Jack and Kate
Mid-Nov. 2004 - Desmond meets other 815ers
Dec. 31, 2004 - O6, Ben, Desmond and Frank leave the Island
LBs start skipping through time
2007 - Ajira 316 crashes on Hydra Island
Sun and Lapidus take outrigger to abandoned Dharmaville and meet Christian Shephard
2007 Crash date + 2/3 days - resurrected Locke found on Hydra Island; Ben in Ajira infirmary
And now for the Time Skips
Episodes 1 and 2
2005 LBers go to date of Nigerian plane crash
Then to post-Swan implosion time
Then to somewhere between 2001-2004 when Desmond is in Swan Hatch
Then to 1954
Then to Nov. 1, 2004 where they come across a lit up Swan Hatch and Aaron's birth
Then to some future date where the beach camp exists, but has been raided by people in two outrigger canoes and the Zodiac is missing
Then to the day Rousseau's people crash on the Island
Episodes 5, 7, 8
The flash when Locke falls down the well takes them to 4-toed statue days
Locke turning the wheel takes the remaining LBs to 1974
Sayid is in 1977; Sun, Ben, Locke, Lapidus in 2007
Episode 10 - 1977