I am seeing more kindergarten students on a regular basis this year. Over the years, we have become much less software based and much more web focused. Although I have many good sites for this age on my Early Learning page, the trick is to get the kids to the sites. My solution is to create a tizmo for them, which is much more visually based.
Some of my favorite sites for this age are:
Bembo's Zoo, an alphabet site that morphs an animal word into the shape of that animal
Starfall, a site where children can learn the alphabet as well as a very well done phonics based reading program
Literacy Center, a place to practice skills with upper and lowercase letters, numbers, colors, and shapes
Building Language for Literacy, a Scholastic site with three different activities, initial consonants, sorting words based on location, and rhyming words
Count Us In, a math site with fifteen activities covering counting skills, patterns, basic addition and subtraction as well as others