I am just playing Diablo 2 for the first time (I purchased the Battle Chest) and I am enjoying it. However, I can't seem to find how to open a world map. I have pressed every key and looked through the game windows, but I still can't find one, and I feel like I am just blindly running around.
If anyone could tell me how or if it is possible to open the map, that would be great.

I think the default key for the automap is Tab, but the map doesn't show you where to go as it only gets filled in as you wander around.

Yep, just hit TAB and you pull up the map.

There is no world map. There is the region maps that the other people mentioned but no world map.
However this is usually not a problem since its not too hard to figure out where you are supposed to go. Most maps have only 1 or 2 area transitions anyway, of which one is usually a dead end that involves a quest you have to do there, whereas the other is the actual continuation.

Thanks a lot!

Hang onto wirts leg ;)

Once you have played LOD till you're sick of it, you might want to have some fun with the items on Death Jester's Diablo 2 Items All of the weapons and armor that you played hours and hours to find, but never did, are available for download. With a hero editor you can give LOD one last play thru like you always wanted to play it.
You have to be careful, built one character with weapons and armor so powerful that enemies burst into flame as I approched them, never getting close enough to use those weapons, had to build him down some. Was fun for a last play thru.. . . =)

Yea you can get it as many times as you want, but its a pain on singleplayer because you need to reset all the levels and monsters. Also added that as a bit of a hint incase he doesn't know about the secret level, being the first time playing and all.

I'm looking forward to the cow level.

Yeah, but I also think it's a pain having three inventory slots taken up by the bloody thing all through the game.

Cow level's for kids
Uber Tristram rules!

Its not to bad if you throw it into the stash, assuming your not a pack rat. If you are there are some nice mods you can get that increase inventory and stash size quite a bit.