STL files commonly used for 3D printing (stereolitography) can be exported to all kinds of other 3D modeling / CAD formats, including VRML format. Some viable software capable of stl to vrml conversion are listed below, but it can most likely can only be used to convert meshes.
Open STL file Open VRML file3D viewer and converter with huge file type support
A professional manufacturing data preparation software
A Mac version of the popular 3D visualisation software
A converter for 3D formats
A CAD conversion software
Creo Parametric (formerly known as Pro/ENGINEER) is a complete 3D CAD software solution by PTC
An open source multiplatform 3D CAD/MCAD/CAx/CAE/PLM modeler
A command line converter for 3D format
A 3D mesh converter