Recently, I was trying to watch some Buffy the Vampire Slayer and Angel crossover episodes in order (I watch them while I exercise in the morning). I couldn't figure it out using the guide booklets that come with the boxed sets, so I did a quick search of the Internet. I quickly found a chart by Simon Hampel. Thanks, Sim'! I then turned the chart into a list, which can be copied and pasted into Word, printed small, and tucked neatly into a boxed set. You're welcome. Warning-TONS of spoilers.
Buffy and Angel Crossover Episode Guide
B 4-1 The Freshman -Angel calls Buffy but says nothing.
A 1-1 City Of... -Angel moves to L.A, saves Cordelia.They team up.
B 4-3 The Harsh Light of Day -Oz agrees to take a ring to Angel for Buffy.
A 1-3 In The Dark -Oz gives Angel the ring in LA.
B 4-8 Pangs -Angel visits Sunnydale without telling Buffy.
A 1-8 I Will Remember You -Buffy visits L.A. and Angel, who becomes human.
A 1-10 Parting Gifts -Wesley, a “rogue-demon hunter,” joins the team.
B 4-15 This Year's Girl (Part 1)-Faith wakes up from her coma.
B 4-16 Who Are You (Part 2) -Faith takes over Buffy's life.
A 1-18 Five By Five -Faith is in L.A., being a bad girl.
A 1-19 Sanctuary -Buffy comes to L.A. to take on Faith.
B 4-20 The Yoko Factor (Part 1)-Angel comes to Sunnydale and fights with Riley.
A 1-22 To Shanshu in L.A. -Darla (staked in B1-7 by Angel), is resurrected.
A 2-1 Judgment -Angel visits Faith in jail to see how she is.
A 2-9 The Trial -Drusilla comes to L.A.
B 5-17 Forever -Angel comes to Sunnydale to comfort Buffy.
A 2-17 Disharmony -Harmony comes for a visit in L.A.
A 3-1 Heartthrob -Angel retreats to grieve over Buffy's death.
A 3-4 Carpe Noctem -Angel learns Buffy is alive.
B 6-4 Flooded -Buffy leaves to meet Angel.
A 3-5 Fredless -Angel returns from meeting with Buffy.
B 6-5 Life Serial -Buffy returns from meeting with Angel.
A 4-13 Salvage -Faith breaks out of prison to help fight Angelus.
A 4-14 Release -Faith fights Angelus.
B 7-17 Lies My Parents Told Me- Willow gets a call from Fred in L.A.
A 4-15 Orpheus -Faith’s in Angel’s/Angelus’ mind. Willow comes to L.A.
B 7 -18 Dirty Girls -Willow brings Faith back to Sunnydale.
A 4-22 Home -Angel is given an amulet by Wolfram and Hart.
B 7-21 End of Days -Angel returns to Sunnydale to help Buffy.
B 7-22 Chosen -Angel gives Buffy info. and a mystical amulet.
A 5-1 Conviction -Harmony joins the team in L.A.
A 5-2 Just Rewards -Spike is resurrected in L.A. and joins the team.
A 5-10 Soul Purpose -Buffy appears in Angel's nightmares (at least her voice).
A 5-11 Damage -Andrew appears in L.A. searching for a slayer.
A 5-20 The Girl In Question -Angel and Spike rush off to Italy to try and protect Buffy.