Hi Thomas,
You can download Eclipse from www.eclipse.org. And the Real View Debugger from http://www.arm.com/products/tools/software-tools/rvds/index.php.
Best regards.
Jorge.
Basically any JTAG tool, supporting ARM926 may be applied with i.MX28.
In addition please look at recommended devices in Emulators/Probes section :
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=i.MX283&nodeId=018rH3ZrDRA24A&fpsp=1&tab=Design_Tools_Tab
Also the following may be interesting :
https://community.freescale.com/message/276989#276989