Recently I moved a site to a new hosting company. After pointing the name servers to the new host, the site has been switching back and forth between the old server and the new server. I know that it takes 24-48 hours to fully propagate. Here's the strange thing. Sometimes I get the old server in one browser and the new server in another browser. For example, in Firefox I am able to see the site on the new server and browse around. In Opera, I am seeing the older server even after completely clearing the browser cache. This has been going on for the past two days. Has anyone else seen this? Very strange.
If 48 hours have passed then don't worry. Your domain name has fully been propagated. You are getting 2 different servers in two browsers because of dns caching. Try to clear your dns cache. How to Flush DNS in Microsoft Windows In Microsoft Windows, you can use the command ipconfig /flushdns to flush the DNS resolver cache: You can also use the command ipconfig /displaydns to view the DNS resolver cache. Turning off DNS Caching under Microsoft Windows If you experience frequent issues with DNS caching under Microsoft Windows, you can disable client-side DNS caching with either of these two commands: This will disable DNS caching until the next reboot.
as stacman said, alot of ISP's cache DNS, i know my one (Virgin Media) in the UK cache for 48 hours which can be a HUGE pain sometimes!