Had a problem developing a WCF service to grab data out of Sitecore, which is running on IIS 7.5 in my dev environment. I published the service in the config-free manner, but was getting an error:

the requested content appears to be script and will not be served by the static file handler

After searching around for a bit, I found a post on the MSDN forums that responded to a different error message, but the solution worked for my problem also:

You will need to run ServiceModelReg.exe -i from the “%windir%Microsoft.NETFrameworkv3.0Windows Communication Foundation” directory to register the script maps

To quote MSDN:

Registers this version of WCF and update scriptmaps at the Internet Information Services (IIS) metabase root and for all scriptmaps under the root. Existing scriptmaps of lower versions are upgraded to this version.

Installing: Machine.config Section Groups and Handlers (WOW64)
Installing: Machine.config Section Groups and Handlers
Installing: System.Web Build Provider (WOW64)
Installing: System.Web Compilation Assemblies (WOW64)
Installing: HTTP Handlers (WOW64)
Installing: HTTP Modules (WOW64)
Installing: System.Web Build Provider
Installing: System.Web Compilation Assemblies
Installing: HTTP Handlers
Installing: HTTP Modules
Installing: Protocol node for protocol net.tcp (WOW64)
Installing: TransportConfiguration node for protocol net.tcp (WOW64)
Installing: ListenerAdapter node for protocol net.tcp
Installing: Protocol node for protocol net.tcp
Installing: TransportConfiguration node for protocol net.tcp
Installing: Protocol node for protocol net.pipe (WOW64)
Installing: TransportConfiguration node for protocol net.pipe (WOW64)
Installing: ListenerAdapter node for protocol net.pipe
Installing: Protocol node for protocol net.pipe
Installing: TransportConfiguration node for protocol net.pipe
Installing: Protocol node for protocol net.msmq (WOW64)
Installing: TransportConfiguration node for protocol net.msmq (WOW64)
Installing: ListenerAdapter node for protocol net.msmq
Installing: Protocol node for protocol net.msmq
Installing: TransportConfiguration node for protocol net.msmq
Installing: Protocol node for protocol msmq.formatname (WOW64)
Installing: TransportConfiguration node for protocol msmq.formatname (WOW64)
Installing: ListenerAdapter node for protocol msmq.formatname
Installing: Protocol node for protocol msmq.formatname
Installing: TransportConfiguration node for protocol msmq.formatname
Installing: HTTP Modules (WAS)
Installing: HTTP Handlers (WAS)