CrosswordMaker!
This is the demo puzzle with a 15 x 15 grid. I put this together in less than 5 minutes with CrosswordMaker, so it's a bit rough, there's a misspelled word, and the clues are horrid! :-) However, this is just to give you an idea of what you can do with it. For me, the fun part is trying to get enough words so that the puzzle looks filled up and then thinking up the clues to match the words. Below, the solutions are in parentheses next to the clues so that if you wish, you can solve the puzzle. The real puzzles generated do not give the solutions.
                 
                                                                 
                                   
                                   
                                                           
                       
                                                                       
                       
                                                                             
                       
                                                                 
                                                                             
                                               
                                                                                   
                                               
 ACROSS

1. Free floating organelles within the cytoplasm (mitochondria)
2.wonderful (terriffic Yes, I know it's spelt wrong!)
3.two __ beating as one (hearts)
4.and/___ (or)
5.wicked (evil)
6.lodging (housing)
7.cheese (gorgonzola)
8.ridiculous (nonsensical)
9.contaminating (fouling)
10.vending (selling)
DOWN

1.of interest (interesting)
2.mapmaker (cartologist)
3.boorish (oafish)
4.working with needle & thread (sewing)
5.selected (chosen)
6.chopping implement (axe)
CrosswordMaker v1.0beta is Copyright © 1998 Kristina Pfaff-Harris and can be found at http://www.linguistic-funland.com/scripts/.