Updating a To-Do List and Calendar

I would like to develop a To-Do list and a Calendar that can be posted on my website for 4 people to constantly update. I have tried doing this through VPN and contact manager software to my in-house server and it is "too difficult" for the sales people to handle. So I thought if there were a simple way for them to go to our company website, login, and then just update a calendar and "what I did today" list - they would actually do it - and we could keep up to date. The commercial solutions are overkill - I don't need a myriad of applications - just one simple place for 4 people who are located all over the country to stay in touch.

My website supports MySql, perl, php, and python programming. Can this be done by a person with limited programming experience and simply? Or is it a major application development situation. If it is doable, please point me to the right tools to use to do this.

Thanks.