Open Data Kit includes built in publish data function to send completed data to an online database and from there, link in with Google's Fusion Tables and Earth.
Heukels high quality Dutch flora determination app €9,99
Audubon field guides
National Goegraphic Bird guide
Sibley eGuide to Birds
Cornell Lab of Ornithology Birdseye
Guide to Trees of U Florida Campus
Guide to Trees of OSU Campus
NY Flora Association Blog: A list of field guides for iPhone/iPad has been put together by the NY Flora Association and can be found here. It includes guides to everything from plants to mushrooms.
Mapping, GIS, & GPS
GPS Essentials
iGIS
MotionX GPS
ArcGIS
Google maps/Google Earth
gvSIG mini
GPS Status
Nokia Maps: independent of a data signal (maps preload) and provides voice navigation, tilt and night views, 3D cities, and numerous gps-enhanced services as well as syncing with their full program on a PC
EveryTrail: record trip route, add photos and videos, share route, and download to google earth
PhenoMap: map plantphenology; upload images to a Flickr group.
WolfGIS
GISRoam
QGIS for Android (Uunder development)
Field Work Utilities
Random Numbers
Smart Measure: rangefinder; measure the distance to and height of an object
Theodolite: overlays real time information about position, altitude, bearing, range, and inclination on the live camera image
EMD Periodic Table of Elements
TASA Geotimescale: timeline of eons
Molecules: 3d models of molecules and enzymes
Citizen Science
Project Budburst: national field campaign designed to engage the public in the collection of data on timing of leafing, flowering, and fruiting of plants
What’s Invasive!: submit geotagged photos and observations of invasive species
IveGot1: Identify and report Invasive Species in Florida
Nature's Notebook Android App: from USA-NPN's. Record observations on hundreds of species of plants and animals, as well as add new locations and species to your list in the field.
iMapInvasives:online tool for invasive species reporting and data management.
the USDA National Agricultural Library has a webpage with smartphone applications for invasive species monitoring and identification: link
Teaching Tools
Skeptical Science
GeographCA
R Instructor: an interactive and multimedia tool designed to facilitate the learning process of R.