I. Web-based GIS **
II. ArcExplorer Java Edition for Education (AEJEE) **
III. Windows-based tools under BootCamp
IV. Windows-based tools under Parallels
V. Windows-based tools under VMware Fusion
VI. My World

Un-retouched screenshot of Intel-based Macintosh running AEJEE-Mac (lower left) and Web browser with ArcGIS Online (upper left) in background, and, at the same time, Parallels running Windows XP, with ArcView (lower right) and ArcGIS Explorer (upper right).

I. Web-based GIS
Online mapping is the way that many students and educators are now getting engaged with GIS. It is a powerful option, totally appropriate and satisfactory for many. Using Web-based interactive mapping tools, students and teachers can learn that they get to control the map, and begin to understand some important principles of cartography (scale, projection, symbolization, etc) simply by seeing lots of maps. Examples here include:

The ESRI EdCommunity Web Maps http://edcommunity.esri.com/maps
National Geographic Map Machine http://www.nationalgeographic.com/mapmachine
The National Atlas http://nationalatlas.gov
Geospatial Onestop http://geodata.gov

II. ArcExplorer-Java Edition for Education (AEJEE)
http://www.esri.com/aejee
This cross-platform tool designed expressly for educators was introduced in 2004. Built in Java, AEJEE runs well under MacOS 10.4 and above, as well as Windows XP and Vista. This free, downloadable, lightweight tool allows users to view GIS data from local sources (hard drive or LAN) or ArcIMS servers over the Internet. It can save and open projects, and users can share these even across platforms. AEJEE has simple layout and catalog similar to ArcGIS Desktop. It has several classification options, substantial flexibility for symbology, and can do complex queries, buffers, and even some geographic selection. It can create point shapefiles from XY tables (like GPS data files) and handle hotlinks (using absolute paths) to web addresses or any registered file type. For many beginning GIS users, on either Macintosh or Windows, AEJEE has all the power needed. The very important intro set of lessons is built into the installation, in the \ESRI\AEJEE\DATA\LESSONS folder, and can be accessed from the Help menu. Find more information about AEJEE.

III. Windows-based tools under BootCamp
http://www.apple.com/macosx/bootcamp
Apple has released a product called BootCamp, available for MacOS 10.4 and higher, which allows the Intel-based Macs to load a full version of WinXP or above, and run Windows applications at "full speed." Upon boot-up, the user chooses to boot into MacOS or into Windows. Testing done by ESRI staff and others seems to confirm that such a setup is indeed able to run Windows and applications at "full speed", and that ArcGIS applications are able to run even heavy-duty analytical operations very swiftly. The user must have a properly licensed copy of WinXP or above and must be facile with running Windows.

IV. Windows-based tools under Parallels
http://www.parallels.com/en/products/desktop/
Parallels has a "virtual machine" product called Parallels Desktop for Mac which allows the Intel-based Macs to load a full version of Windows (many versions) and run applications at "high speed." The user can move back and forth between Windows and MacOS applications. Testing done by ESRI staff and others seem to confirm that such a setup works quite well, and current versions of ArcGIS applications (including 3D applications) run swiftly even for analytical operations, though perhaps not quite as fast as on a native PC or under BootCamp (since memory is split between the two operating systems). Here again, the user must have a properly licensed copy of Windows and must be facile with running Windows-based applications.

V. Windows-based tools under VMware Fusion
http://www.vmware.com/products/fusion/
VMware has released a "virtual machine" product called Fusion which allows the Intel-based Macs to load a full version of Windows (XP and above) and run applications at "high speed." The user can move back and forth between Windows and MacOS applications. ESRI staff has not tested Fusion but reports from others indicate that such a setup works well, and current versions of ArcGIS applications run swiftly even for analytical operations, though perhaps not quite as fast as on a native PC or under BootCamp (since memory is split between the two operating systems). Here again, the user must have a properly licensed copy of Windows and must be facile with running Windows-based applications.

VI. My World
http://www.geode.northwestern.edu/myworld/
Northwestern University has developed a GIS called My World, which engages ESRI's MapObjects Java technology. My World is distributed by Pasco Scientific (http://www.pasco.com/myworld/). Built in Java, My World runs on Macintosh OSX and Windows environments. It provides a subset of capacities from a professional GIS environment, including multiple projections, table and map view, hyperlinks, and a common language approach to conducting analyses. It provides a powerful alternative for schools seeking tools that do not require Windows.

Recommendation:
For educators just getting started with GIS on Macintosh OSX, AEJEE is a good choice, as a free, lightweight, introductory tool. Anyone needing full capacity GIS on Macintosh hardware should consider BootCamp or Parallels, which can run ArcGIS under Windows at or near full speed.