I'm wondering if there are any commercially available or open source scripts that would allow teachers at a school to post daily homework assignments, announcements, etc

I'm looking for something fairly simple. I'm currently setting up modified WordPress installations for teachers, which is a pain to upgrade when a security release is made.

Any ideas or suggestions? Thanks!

you can try .lrn - dotlrn.org (used it when I was in university and it's fairly good). The bad thing about it is that it requires lots of memory/CPU (you'll probably need to install it on a box at your school).

Similar to dotlrn.org, there are others such as:

Site@School (http://siteatschool.sourceforge.net/)
atutor (http://www.atutor.ca/)
moodle (http://moodle.org/)
Claroline (http://www.claroline.net/)
dokeos (http://www.dokeos.com/)
LogiCampus (http://www.logicampus.com/) (seems to be offline right now)
Segue (https://segue.middlebury.edu/index.php?&action=site&site=segue)
Wordcircle (http://www.wordcircle.org/)
doceboLMS (http://www.docebolms.org)
iPeer (http://ipeer.apsc.ubc.ca/ipeer_site/)

I actually did one for my Art class, (I thought I was gonna get extra credit), because the professor wasn't able to use BlackBoard.

Teacher ended up able to use it and thus didn't use my system :(.

Anyway I released it yesterday as LGPL, you might want to give it a try:

http://www.free-php-scripts.net/P/School_Board

Basically there is an admin page where teacher can add/edit/remove readings, assignments, announcement and links. Assign. and readings can have as much attachments as needed.

Peace,

I'm wondering if there are any commercially available or open source scripts that would allow teachers at a school to post daily homework assignments, announcements, etc
Did you consider using a wiki? You can have a "read-only" part for your postings and a "read-write" part for your studentes. This way you can receive feedback, they can work collaboratevely...and you can track their participations (wikis has page history)

If you know a little programming, you can tweak any existing wiki engine to fit your
needs.

There is Blackboard from blackboard.com, personaly I hate it.. But it has the features you'll need already setup and lots of other stuff like online assignment submition, forums, file repo and form-based exams.