we are currently setting up a situation just like this. what type of router are you using? we have a cisco router and we use the cisco vpn client on the laptops. the cisco vpn client connects them to our local network with a secure tunnel. then it is just as if they were on the network here at work. then they can run outlook, etc.
as far as the phones, I have just recently installed a Shoretel VoIP phone system. after the vpn is connected all I do is start the shoretel client on the laptop and choose softphone. that connects them to the phone system and assigns their extension from the office to their laptop. all they need is a headset with microphone and it acts as if they are on their phone in the office. Shoretel also has a client for mobile phones too. so they can use their extension on their cell phone too. That part is new and I have not tested it though. The client via the laptop works great as long as they have high speed internet.
for the meetings you could use netmeeting or Shoretel also has a conferencing bridge that can be added to the phone system which includes desktop sharing and all. It truly is a great system. (and for the record, no I do not work for Shoretel, just love the product 🙂 ).