Alternatives to WebExOne for intranet apps?

I work for an organisation which has staff embedded within other organisations with different IT arrangements. We have been using WebEx for intranet apps – calendar, documents, polls etc, but its not cheap and I feel there must be other alternatives out there.
I’m currently looking at Google Docs & Calendar, with SurveyMonkey for polls, but are there any PHP scripts for example, which do this sort of thing and could be hosted somewhere?
TIA
Geoff