vim-pyflakes

This is a vim plugin to automatically highlight errors in your program code as you're editing. It requires PyFlakes to run. When installed, it will highlight any errors pyflakes finds on the fly.

Screenshot

Editing a file with vim-pyflakes enabled. Note that there's a missing = in the if clause of the highlighted line; as soon as I hit enter, it was automatically highlighted and an error message printed in the statusline.