I have found my all time favorite preschool learning program. Max's Early Learning is working wonders with my 5-year old son. This program is very complete. It comes with 20 short movies on two DVDs, 23 vocabulary games on two CD-ROMS, 20 fun songs and story audio tracks on two audio CDs, 58 pages of vocabulary worksheets in two workbooks, 35 pages of alphabet worksheets in one student workbook, and one alphabet/phonics audio CD.
Before this program, I was lucky to get my son to put in 20 minutes of 'school time learning'. He will now literally do between 2 and 3 hours a DAY because he LOVES playing the educational games on the computer. The games reinforce letter recognition, farm animals, number order, colors, family relationships, shapes, transportation, parts of the body, weather and seasons, time of day and more in a fun interactive way. He also enjoys watching the movies and listening to the fun songs while we're in the car.
Check out their website -- they have two other very popular programs called Junior Phonics and The Phonics Game. They also have Math and Vocabulary games. Max's Early Learning is sold for right around $100 (which can be broken into three payments). Considering how much is included with this program (packaged nicely with a handled box), I believe it is well worth it!