You can use a webserver and replication:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnacc2k/html/intrjet4.asp

Or you can connect a pc to the internet and set it up as a VPN enabled server where you can share the database so you and your team can connect to it over the internet.

Windows 2000 server; how to enable VPN:
http://techrepublic.com.com/5100-6268-1032135.html

Connect Windows XP to the VPN :
http://support.microsoft.com/?kbid=305550