RangerWickett said:
Are creature appearances OGC? Could a comic have an image of a 'Beholder,' for instance, or would it be a theft of intellectual property, forcing you to draw them differently?
There was a discussion about this recently on one of the OGL lists. Basically, with monsters, unless their physical description is in the SRD, depicting them in the "WotC-style" is a violation of their IP. Obviously, this isn't going to be the case with things like skeletons or dragons, but if a monster is fairly unique to the game (like the Beholder, Mind Flayer, or Behir), then WotC's depiction is their property.
The best you can do is to discern what you can from the description in the SRD. A quick glance at the Beholder write-up tells you that it's a Large Aberration, has ten small eyes, a central eye of some kind, a mouth (bite attack), and natural buoyancy. It doesn't even mention anything about eyestalks (the "Eye Rays" description could imply that, but it's not implicit). The Bodak is even more vague: The only things that give you an idea of what it might look like is: medium-size Undead; Slam attack; Death Gaze attack; regular movement (so it doesn't fly, burrow, etc). It does mention in the "Flashbacks" quality that it can "...recall its life", but that doesn't necessarily mean that it has a form similar to when it was alive...
While my examples apply to WotC monsters, the same can be said about any open monster, if its physical description or illustration isn't open.
To illustrate an SRD monster other than something that has a common appearance like a vampire, dragon, or orc, it might not be a bad idea to find an artist who isn't familiar with D&D (or the monster you want to illustrate, at least), give them the physical points you can gather from the SRD entry, and let them use their own creativity to develop something new.