Here you have all the most popular crossword seaches done on crosswordsguru.com :
If you only have the first letter(s) of a word, type the letter(s) above.
This tool is useful when you only have the end of a word. Type the letter(s) that finish the word...
You only have the middle of a word ? Try this tool that list you all the words that contain a letter or a syllabe.
This tool allows you to get all the words that fit a number of letters.