Depending on the level of the pupils and there phonetical understanding, the Toe by Toe materials have had an impact on the ‘right’ pupils. There is also The Word Wasp that is by the same publisher and that has been very successful.
Take a few suggestions and approach the companies to come in and talk to you about the scheme and what the impact is (the normally provide a free be as well!). Spending time on researching what is right for you to ensure impact will save you a headache later on or in a couple of years! You might need to get in a handful of different spelling programs for your different learners – eg boys/ girls, Specific need, Sensory learners etc