Sorry, I know this is probably the 50,000,000,000th time someone has asked this question but...

I am about to start watching season 4 of Buffy and season 1 of Angel, at what point should I begin watching Angel?

Yeah its been asked a few times.

http://www.dvdtalk.com/forum/showthread.php?t=399146

http://www.dvdtalk.com/forum/showthread.php?t=364280

http://www.dvdtalk.com/forum/showthread.php?t=351736

http://www.dvdtalk.com/forum/showthread.php?t=345505

http://www.dvdtalk.com/forum/showthread.php?t=315460

http://www.dvdtalk.com/forum/showthread.php?t=272891

I figured, but when I searched for "buffy" an overwhelming 500 topics came up

Thanks!

Basically, you just need to keep an eye out for the crossovers, when stories are begun on one series and completed on the other.

BtVS 4, Angel 1

During the fourth season of BtVS and the first season of Angel there were many crossovers as the new series sought to establish an audience.

Buffy 4.3 The Harsh Light of Day --> Angel 1.3 In The Dark

Buffy 4.8 Pangs --> Angel 1.8 I Will Remember You

Buffy two-parter 4.15/4.16 This Year's Girl and Who Are You
--> Angel two parter 1.18/1.19 Five By Five and Sanctuary
Incidentally, these are four of the best eps in the Buffyverse, IMHO

But when you search "buffy angel viewing order" only six come up.

Yes, there are crossovers, but plotwise they don't amount to much. You'll be fine just watching all of a Buffy season or all of an Angel season. I think that keeps the rhythm better anyway.

While this may be true for some of the episodes, the two double parters mentioned above really need to be watched first. If he did want to watch the whole season in one go, he should at least watch the entire season of Buffy first, then Angel. If I remember correctly, all of the crossovers in the first season of Angel started over on Buffy.

The only one I'm unsure about is the Buffy episode "The Yoko Factor"...