First, the root method. Assuming your device is rooted, you can get the Netflix app to work by making it think your handset is actually one of the supported ones.
Using a root explorer app, such as Root Explorer or ES File Explorer, go to /system, while at the same time ensuring it is mounted as r/w. After backing up the build.prop file, edit it and change the ro.product.model and ro.product.manufacturer line to one of the following:
Reboot your device. Then try installing or running Netflix again. It might work, and we say might because there are some phones that have been reported to refuse to work even with this method, such as the Verizon HTC Thunderbolt.
Also, making this change could affect other apps.
Second, the non-root (and probably safer method):
In this case, we rely on those kind folks at XDA Developers again. XDA Developers member ften has created a some modified versions of the Netflix APK that disables its device check.
Head on over to the XDA forums, but make sure you enable sideloading on your device (or Unknown Sources, as it also known). Assuming you have an AT&T device, we hope you have received the update enabling sideloading.
To enable it on your device, check the "Unknown Sources" checkbox in Settings > Applications.
This should satisfy those of you who can't wait for the slow certification process from Netflix.