I've spent a while trying to find a search engine that will allow me to search for issues with 2 or more characters. For example, I want to search for a comic that includes "Spider Man and Captain America". Is there anyway I can do that?

@gugaprado10: Not this website, and not any that I have ever heard of.

Though if you go to a character page here you can click on the Appearances link under the volume, and this will show any specific appearances in a volume. This could help out as if you are looking for Captain America and Spider-Man, you could look on the Captain America page and find any Spider-Man volumes (you might have to click View All), and presumably they are going to both appear in this same issue. This is not exactly the same as what you are looking for, but might be the best option that you find.

@blueecho: There's actually an easier way, if you go to Wiki>Issues and add the characters via the sidebar filters you can see all issues or volumes (Wiki>Volumes) where they appear just not limited to where they appear in the same issues. The browse pages have a very powerful filtering system.

Google if you use it right.