I'm surprized I couldn't find this one either in the database or in the forum. Here's Robert Johnson's version:

CROSSROADS BLUES
Robert Johnson

I went to the crossroads, fell down on my knees (2x)
I asked the Lord above have mercy, save Poor Bob if you please.

Standin' at the crossroads, I tried flag a ride (2x)
Didn't nobody seem to know me, everybody pass me by.

When the sun go down boy, sun gonna catch me here (2x)
I haven't got no lovin' sweet mama, just to love and feel my care.

You can run you can run, tell my friend boy, Willie Brown (2x)
That I'm standin' at the crossroad babe, I believe I'm sinkin' down.