For pupils' individual blogs "Edublogs" is the best software as it is designed to be used in an education setting and thus has many safety and administrative tools built in.
Setting Up an Edublogs Account
Gmail+ Method for Creating Student Accounts
Setting Up Student Accounts
Using the Dashboard
Writing a Blog Post
For all there is to know about using edublogs in your classroom here is the link to their comprehensive help section:
This website has been created by Paul Leacy (0744034) in 2011 as part of his Final Year Project in the University of Limerick as part of the (B.Tech. Ed.) course in Materials and Construction Technology.