My startup has employees who are in different places at different times. What is the best way to manage and to centralise files, emails, communications, ...? Would the web be the best place to start?
Project Management Employees Communication
There are multiple tools you can use
These should be good enough to start with
You should check out the just released features of Google+ hangouts ("hangouts with extras"). You get free video conferencing with multiple people, real-time shared documents editing, and a real-time shared sketchpad. If you can't collaborate in real-time because of time zones, you can still use shared google documents.
I would suggest HighRise for centralizing your emails to customers.
Basecamp for project management
you can start with a free (or cheap) account and scale up money comes...
I agree with Anurag,
Use remote desktop sharing software while dealing with few unreliable team and find someone reliable very soon.
I use skype email. You can use FTP to showcase work that has been done.