Educational Multimedia is the utilisation of a combination of text, graphics, animation, pictures, video, and sound in classroom instruction aiming to transfer knowledge through attractive representation of information that could engage the student and promote learning. These very diverse educational tools seem to share an assumption that multimedia integration in classroom teaching helps pupils learn effectively. To find out whether there is a possibility for an educational multimedia to promote in classroom learning we need to evaluate the means through an educational prism and a toolbox of criteria. The author in this study attempts to evaluate certain Greek educational multimedia such as an educational CD-ROM as well as an educational web site in an effort to establish the factors that determine an efficient multimedia resource that could promote in class participation and learning. Furthermore an attempt to illustrate the criteria necessary for the design and use of an effective educational web site are set in the last chapter of the work.