As mentioned in today's review, here's the crossover between Invincible and Spider-Man. Specifically, the scene when Mark gets zhwoomed into Earth-616:
Invincible #33 was drawn by Ryan Ottley, who was the book's regular artist by that point; but in a very cool touch, Marvel Team-Up #14 was drawn by Cory Walker, the artist who created the character with Robert Kirkman. Way to tie it together, guys!
It's worth reading both those issues, by the way: on the Marvel side, to see what happens when Spidey introduces him to the Avengers, and on the Image side, to see what other worlds Invincible visits. Let's just say it was a very busy day, and Spider-Man wasn't the only existing character he met.