How can I create a VPN with two LAN each one connected to the Internet by a router?

the problem is the IP is not static and my isp wont give me one. is there an easy software that can help me solve this?
I need to connect my office LAN with my home office and use the printer, file sharing, etc.

try HAMACHI .. hamachi.cc

It can be done, but the equipment it takes depends on several things. In order to use something like a Cisco PIX firewall to do it, you have to have a registered IP address available for the firewall. However, if you use a Snapgear Cyberguard firewall, you can do it using a private IP address on your end (as long as ports 50, 51, and 500 are open). The tunnel has to be configured with your end designated as a dynamic IP address.

The specifics of how to do this are documented with the manufacturer of the equipment you wish to use. Post a more specific question, and you'll get a more specific answer.

Frist make sure your Network Administratror will allow it.

Second you will have to have an accout on each end that supports Dynamic DNS* I you and recommend NO-IP**.

Use one computer as a server at the office network and attach a telephone line to it with automatic answer enabled. From home, start a dialup network by dialing that telephone line and make sure the necessary protocols are in use i.e Client for Microsoft.... and File and Printer Sharing..... Also you will have to leave the server at the office connected to your ISP so that you will have that Static IP for the purpose, whenever you wanna do that! God bless you. (I Think)

i think practically not possible without ip