Case style reference?

Is there a good resource that shows a whole bunch of case styles on one page?
I keep looking up parts on Digikey and finding numbers I'm not familiar with. Sometimes they're almost identical to the pkg I'm thinking of, or maybe they're a better choice. I don't know. I just know it takes awhile to reference a datasheet for a part using that case style, and then they don't always list information on what that package's size and shape.

Be nice if there was one big resource I could consult/browse, but is there any such thing online?

Don't know about on-line, but you can buy NTE's semi-conductor cross reference book at almost any major electronic component supplier for around $3.99. MCM Electronics, Allied Electronics, etc.