Slate has a useful interactive feature up, "The Middle East Buddy List." While of course such a chart must sacrifice nuance and detail, it's a nice resource for a quick glance. If you mouse over the icons, a brief explanation appears of why Slate classified things as they did. As they describe the chart:
Slate's Middle East Buddy List breaks down the relationships between the countries, terrorist organizations, and political factions who are fighting it out in the current conflict. Who likes whom? Who are the bitterest of enemies? And which groups don't really know where they stand?