There are a handful of solutions for this, some better than others, and you can read about them here on Smashing Mag. However, making changes quickly is important, and when you’re running a local server for your dev environment, uploading changes each time to a remote server to test isn’t efficient. I was using Sauce Labs for a while for this, but the uploading after each change became laborious. I now use Browser Stack because it can tunnel into your local environment for testing. No need for running VMWare and installing IE7, 8 and 9. It’s great – works pretty well, and the support team is responsive. Generally speaking, it’s pretty darn cheap too since you can pay by the hour. I’ve been on the same $20 for the past 3 months. Recently they expanded testing to mobile devices which is sweet. Most mobile testers I’ve seen so far stink and don’t account for meta data for device-width, etc.