The American Speech and Hearing Association is one of the best websites for up-to-date and reliable information on all areas of speech and language. Visit Asha.org!
Activities to promote speech and language development for Pre-K and Kindergarten students:
http://www.asha.org/public/speech/development/Parent-Stim-Activities.htm
When working on speech sounds, the general progression is:
http://mommyspeechtherapy.com/wp-content/downloads/forms/artic_therapy_process.pdf
Look around the below website for wonderful ideas and worksheets for specific practice on speech sounds!
http://mommyspeechtherapy.com/?page_id=55
I love these videos on how to produce various sounds!
peachiespeechie.com/pages/peachie-speechie-videos