Map Mashups:
Gramfeed: Gramfeed helps you visualize Instagram on map, you can see where your friends are posting pictures, visualize anybodies Instagram photos on map or search for real-time photos posted at any location.
MisoTrendy: MisoTrendy helps you find the most popular places around any location. MisoTrendy uses trending data from foursquare and shows currently checked-in users, tips and mayorships from the most popular venues in real-time.
Check-in Mania: Checkin Mania is a mashup to track who is checking in various locations around you using the popular location based social media apps like Foursquare, Gowalla and more.
Local Twitter Trends: Mashup of Google maps and local twitter trends from Happn.in, this map will show the top 10 trending phrases in over 80+ major cities around the world.
MashSpots: Local search made easy with this mashup, Mashspots makes it easy to find places around any location without having to know the address of the location you are searching around, just click on any location on the map to get the 4 closest places of interest.
Gaza Attack Timeline: Mashup of Gaza Strip Attacks by Israel showing the Israeli air strikes on Gaza, Hamas rocket attacks, Israeli ground assaults... The map shows the day by day attacks and casualties. Data source from the Guardian.
Mumbai Terrorist Attack Timeline: Mashup of Mumbai Terrorist Attack of 26th November 2008 showing the series of events that took place on the day of attack. Data source from Wikipedia.
US Election Map: Mashup of US Electoral Map and Google Maps will allow you to interact with google maps to calculate 2008 US Electoral votes.This mashup will allow you load the map with previous election results and current polls.
US Senate Map & US House of Representatives Map: Mashup of www.senate.gov and www.house.gov on Google Maps displays all the current United States Senators and House of Representatives with their office address, phone number, contact information and website.
Obama Map:Mashup of Barack Obama's Presidential Campaign speeches and endorsements on Google Maps, this mashup also shows Obama media appearances on the campaign trail and interviews on popluar shows like 'meet the press, Larry King Live, MSNBC Hardball, Jay Leno show, Letterman Show, CNN AC 360, CBS 60 Minutes....
Citysearch Map: This Mashup of Citysearch and Google Maps will help you find the best restaurants, hotels, nightlife, shopping and services in major US cities as voted on Citysearch.com. Get direction to the location or link off to Citysearch.com to read user reviews.
World News TV: Watch live world news IPTV from various TV channels like CNN, BBC, Sky News, ABC News Now, CCTV-9 China, Iran PressTV, France24, CNN IBN India and Russia Today. (Live News TV)
World F1 Circuits: This Google Map Mashup displays satellite images of all Formula One Grand Prix venues from 1950. Click on markers to view satellite images of race track or link off to wikipedia to get information on Grand Prix or race circuit.

2010 F1 Tracks | 2009 F1 Tracks | 2008 F1 Tracks | 2007 F1 Tracks
Amtrak Map: Displays Amtrak rail routes and stations on Google Maps. Click on any Amtrak station to view the route details or link off to Amtrak.com to get detailed schedule information. NEW Full screen Amtrak Map.
Portland TriMet MAX Map: Displays Portland's transit system - TriMet MAX light rail lines and stations on Google Maps. Displays TriMet MAX Blue, Red, Yellow and Portland Streetcar lines.
Chicago Transit Rail Map: Displays Chicago's Metra Rail routes and Chicago Transit Authority (CTA) lines on Google Maps.

CTA | Metra | CTA+Metra


Map Mashup Tools:
Geocoder (Google Maps API): Tool to get latitude and longitude from any point on map, address geocoding, reverse geocoding and client IP geocoding using Google Maps API.

Geocoder (Microsoft Virtual Earth API): Address geocoding and reverse geocoding with Microsoft Virtual Earth API.
KML Creator:
Mapping tools to create polylines, polygon and markers in KML format. Useful for creating transit mashups.
Lat49 Map Ads:Add Lat49 Advertising system for your map mashups and start earning revenue. This mashup shows Lat49 Ad locations and also has basic examples for lat49 Ads integration for Google, Yahoo and Windows Live Maps.

3 easy steps to add Lat49 ads to your Map mashup


iPhone Apps:
iTrends is a simple and easy to use iPhone app that lets you find out "Whats trending on twitter and why it is trending?"
iTrends
MashSpots iPhone App helps you find 4 closest businesses or plaaces of intrests by just clicking any anywhere on the map.
MashSpots
iPhone Web App version of Best of Citysearch mashup. Open on iPhone Safare and save to home screen.
CS Map
"Shake 2 Find" helps you find your favorite cuisines or anything around you, wherever you go.
Shake2Find
Get satellite images of all Formula One Grand Prix venues from 1950.
F1_Circuits


Google Mapplets (My Maps):

Mapplets are user created map mashup applications that run on Google Maps website, which can be accessed by clicking on "My Maps" on maps.google.com page. Multiple mapplets can be added on Google Maps to make mashup of mashups.

Formula One Circuits

Chicago Metra Rail Map

Portland Transit TriMet MAX

Amtrak Map

Best of Citysearch

US Electoral Map

Mumbai Terror Attack Timeline

Gaza Strip Attack Timeline

Mashspots

Checkin Mania


Google Map Gadgets:

Google Map Gadgets are user created map mashups that can be easily added to any website using a small snippet of code.

2008 US Electoral Map

Obama Video Map

US House of Reps Map

US Senators Map

Citysearch Map

Mumbai Terror Attack

Gaza Attach Timeline

MashSpots