Just a quick note and 2 links – I am finishing up my Homeschool Tracker lesson plans and added a link for them. They are using Worldly Wise for both vocabulary and spelling. Worldy Wise 3000 offers some very nice resources for both students and teachers. For the students, each lesson has a section where the vocabulary word is pronounced and the student is asked to repeat it. Then, the definition is orally provided. Finally, a sentence is spoken and then the child determines if the word was used correctly. Additionally there are games available for each lesson including Hangman and a crossword puzzle.
My additional link for those not using Worldly Wise, is a site called Spelling City. This free resource allows you to create an account if you wish to save the spelling lists you create. Then, you type the words into the list and your student can then listen to the word being pronounced and spelled and a definition is offered. After the student has studied the words, he can then take a test for that lesson. The student clicks the Say It button and the word is spoken. If necessary, the student can also click Sentence to hear it used in a sentence. A space is provided for the student then to type the word in.
One caveat is that some words may not yet be added to the dictionary. You would need to find an alternate way to teach those to your students.
One additional resource that is not free but has been mentioned as a good resource is Spelling Time.