I grew up going to DL and it has a special place in my heart. WDW uses the name world b/c it is large. DL is a land.
Definitely check the DL forum here on the DIS and you'll get a ton of information. There are several 'sticky' posts at the top of the DL forum from HYDROGUY and he has summarized a lot of the differences and does a fantastic job comparing the two parks.
Here is the link:
http://www.disboards.com/showthread.php?t=1520483
Go to the one DL for WDW vets and you will find a great deal of comparison info.
DL is a great park and does have a few different rides -- the main one being Matterhorn. Matterhorn is the central focus at DL b/c you can see that mountain from all over the park. Of course the castle is right in the center down Main Street but it is small (about 25% smaller than MK at WDW) compared to Matterhorn.
The big difference you'll find is the size. It's not as spread out it seems. But, don't be sad b/c you can't ride It's a Small World. It is closed for refub until late Nov. (boo hoo!).
A lot of it will be very familiar -- Rail Road, Main Street, many of the rides. Others will be very different. PotC is waaaaaay better at DL than at WDW.
If you like WDW you'll like DL too. It is very geared to locals rather than vacationers like WDW. While a lot of people go to DL for vacation, on a Saturday there will be a lot of locals. After labor day schools will have just gone in to session so there may be a bit less of a crowd but it will still be busy.
At DL you go thru security bag check then you get in to the open space between DL and CA (California Adventure). You can then enter into either park easily if you park hop. Downtown Disney is just outside the security check and is much more easily accessed than at WDW. You can even take the monorail from Tomorrowland (one HUGE difference from WDW -- you can actually ride the monorail as a ride b/c it stops inside the park) to DTD.
If you have time, definitely go. If nothing else it will satisfy your Disney craving.
Enjoy yourself!