Grunge is an irregular and dirty style in visual art, but it is a popular trend. Even a simple touch of grunge style can change perception of your Illustration. Most frequently used elements in such disgusting visualisation are: rasty spray, splats, halftones, drops.
Vector illustrations can be edited in many computer art programs, for example: Photo Styler, Flash, Xara, Corel Draw, PMView, and sure All Adobe programs Photoshop, Illustrator, Indesign etc. can be used to open and edit vectors. Illustrator CS3 my certain choice!