The USNaviguide website has an assortment of Google-Maps-based services for mapping the boundaries of various geographic parameters:
Zip Code: Enter a 5-digit zip code, or the first three digits of a zip code, and get a map of the area covered by that zip code. Or click on the map, and get a map of the all the zip codes in that area, with a placemark at the location you clicked on with the zip code for that area in the info bubble:

City/town boundaries: Enter a zip code, or click on the map, and get the boundary of the city/town jurisdiction for that area where appropriate:

County/FIPSCSA: Enter a zipcode, or click on a spot, and get a map similar to the one above for either a county or a FIPS (Federal Information Processing Standard) Core-Based Statistical Area, with a placemark near the center of the polygon with the relevant information, including code numbers.
There is also a US geocoders (get a latitude/longitude for an address), and a reverse geocoder (enter the lat/long or click on an address, and get back the closest addresses to a point).
The related Maps.Huge.Info site has links to most of the above services, but also a few more as well:
- US telephone area code maps
- Plotting zip codes by line boundary instead of overlay map (as at the top)
- Australian post codes
- A zip+4-based reverse geocoder
Finally, there’s a page of the free PERL code they use for converting a polygon of points into a Google Maps polygon.
Other posts in the Google Maps Tools series
- Coordinate Data From Google Maps
- Reverse Address Geocoding With Google Maps
- Converting Google Maps Search Results To GPX
- Coordinate, Elevation, Distance And More In Google Maps
- Google Maps "My Maps" Features
- Measuring Elevation, Distance And Area In Google Maps
- Creating GPS Routes In Google Maps
- Thematic Polygon Shapefile Display In Google Maps
- Using The Google Maps Interface To Display General Maps And Images
- Heat Mapping In Google Maps
- Elevation Profile In Google Maps
- Embed Google Maps "My Maps" On Your Web Page
- Real-Time Website Visitor Plotting In Google Maps
- Customizing Google Maps Markers
- Two Fun Cartographic Google Maps Tools
- Simple Guide To Embedding Google Maps "My Maps" On Your Own Webpage
- Another Google Maps Geocoder/Reverse Geocoder
- Drawing Lines Between Points In Google Maps, Straight And Great Circle
- Convert A Google Maps Point To Multiple Text Geographic Formats
- Meet Your Friends Halfway
- Plotting Swivel Data In Google Maps
- Meet Your Friends Halfway II
- Geographic Midpoint Calculator
- GIS-Like Functionality In Google Maps With ZeeMaps
- Creating GPS Waypoints Online From The USGS Geographic Names Information System (GNIS)
- MapMyRide.com
- Exporting KML Data From Google Maps MyMaps To A GPS
- Advanced Tool For Embedding Google Maps MyMaps On Your Website
- Draw/Label On Google Maps, And Generate GPX/KML/Embeddable Maps
- Another Way To Create Embeddable Google Maps With KML Data
- Documenting A Journey With Maptales
- Plot A Coordinate Position On Different Map Pages
- Worldwide Reverse Geocoding With Google Maps
- Google Maps Shaded Relief Site Updates
- Digipoint 2: Export Of Google Maps Points In Multiple Formats, And Elevation Data
- Google Maps Line Tool Now Supports Distance Measurement
- Geographically-Linked Video With VeoGeo
- Recent Google Maps Tools
- Google Maps Mapplets From Zonums Software
- Maximize Google Maps With Google Maps Max
- Mapping Zip And Area Code Boundaries, And More
- Altitudes And Terrain Profiles In Google Maps
- “Friendly” URLs To Address Maps
- Quick Zip Code Information
- Simple Online Form For Creating An Embeddable Google Map
- Embed Synchronized Google/Microsoft Virtual Earth Maps On Your Website/Blog
- Worldwide Contour Lines In Google Maps’ Terrain View
- Plot Gazetteer Features In A Google Maps Interface
- Antipodes Map
- New Features At MapChannels.Com


I would recommend http://www.zipcodesmapped.com/ for any US zip code map.
You can use this to find any US zip code maps. You can search by (City, State OR Zip). they have all the maps showing zip codes and major mile streets in all of the united states. The service is free. Search for five Digit Zip Code and find the Maps for all 50 states. A Free ZIP Code Finder which can do wonders for you. Zip codes