Thanks for the replies - I know phplist but it requires importing settings which do not work well with hebrew.

I have 3500 students in my college, and I already have mailing system which totally sucks - I can't even send pictures and it has lots of bugs (big companies like the one that gives service to my college just can't handle simple tasks because of all the bureaucracy).

Anyway, I found out that I can do something myself, for free, better than a company that will do it for 2000$ and worse. The problem is - because it's very buggy, I cannot export the mail addresses from that system to a different one so I sent everyone mail asking them to fill out a form I created using google documents (excel sheet - very useful). So there I have I another address book with 3000 students registered. now I can export it as xls or csv and import in a different mailing program.

Because I use google calendar and google documents I thought it would be easier to use gmail as my mailing platform because when I create a form I can invite people to fill it out directly from their mail - something that is not possible in other programs. Same goes if I have an important even - I can just sent invitations from google calendar, it's very easy. I've managed to send mail to 140 people in my address book, but I haven't tried more than that.