The AVCHD format has been widely adopted by manufacturers, both for consumer and prosumer cameras alike. Unfortunately Adobe Premiere Pro and Premiere Elements don't yet support the format. As one might expect this has generated considerable consternation among Adobe's user base. You can read some of that here.
While it's important to add that Adobe has introduced a workaround, essentially a $450 plug-in from MainConcept, there are Windows-based nonlinear editing programs that already support AVCHD. The two most prominent are Sony Vegas 8.0 and Pinnacle Studio.
No doubt Adobe is behind the eight ball on this one. I suggest that until Premiere Pro and Elements support AVCHD, Adobe should provide the plug-in at no charge to its CS3 customers and free upgrades for CS3 and Elements 4.0 users when the application finally supports the codec.