I'm specifically interested in a webmail service, but I will appreciate suggestions to replace other components too.
Zoho offer a pretty comprehensive range of products, most of which are free for a limited number of users/projects/whatever...
- Office for Microsoft Sharepoint
Even though the functionality overlaps, they integrate with Google Apps in some places, so you could have a hybrid solution.
Microsoft officelive has web pages, email, etc. for your domain.
Yahoo is still alive, at least as for webmail. See this.