There's supposly a second in development
That's been floating around for years. The rumor was to have Tony Twist in it, but McFarlane went through that legal battle with the hockey player Tony Twist (douche), got obsessed with his baseballs, then there was the thing about a fourth season of the cartoon, and now interest in Spawn has virtually dwindled to the few die-hard fans that have stuck around since issue 1. I really don't think a sequel will happen. I'd like it to, but I highly doubt it.