I think i will try to present some uses of blogs in education. These are my ideas and you can probably refine them so they suits your situation better.
When you send your students to the library and use the computers there they probably aren´t able to save the information on a secondary memory. Also it is better to collect the information at one place so you can reach it everywhere. If you collect the information and links in a blog you can use the information anywhere as long as you got internet connection. This will be the students own data and link bank which they can use, when they will critical select the information. Be clear that they should always store the source of the information. This need not be published on the net since you can in Blogger save as draft.Writing Essay
The fact that students get feedback on what they produce and publish on their blog will spur them to write more and also try develop their language skills. They will get comments from other students and of course from others on the net. This will give the students incentive to better their language. The teacher comments on the errors and give directions how to improve the text through email. The student can then simply correct and rewrite it on the blog. It is possible to create a blog where students are coauthors and you the administrator thus you have the control over the comments and are able to prevent other students to be mean to each other. Here its important to be aware.Listen and understand
Here you either can link to an audiofile from a internetsource or why not record your own and maybe you can cooperate with another teachers. Here is an example about threatened whales
this could of course be in french or spanish. The student learn about the language and at the same time a different subject. You can present the questions in the same post. If students wonder about anything you got comments as a way to communicate.
Radio via Blog
In the same way as the teacher put their audiofiles on the blog the students can "broadcast" their own radioshows. Blogger and feedburner together can work as a podcast that you are able get it using iPodder and easy transfer it to your iPod or MP3-player.
Schoolpaper online and offline
Of course blogs are an easy way for your students to produce their own schoolpaper. Doing it on a blog thus making it on the web and offline at the same time. The XML files are good quality also if you want to print them out. For this you might to have to make a suitable template. Schools with harsh budget can use this tip. Using blogs doesn´t require expensive software but you get a good print out.