A. Start with iMac Community
https://discussions.apple.com/community/desktop_computers/imac_intel
B. http://www.apple.com/support/imac/intel/
Has all the direct fimrware updates, downloads, articles of interest
C. Internet Recovery feature is only available to (or was) 2011 modes
iMac EFI Update 1.7
This update enables Lion Recovery from an Internet connection and includes fixes that resolve issues with Apple Thunderbolt Display compatibility and Thunderbolt Target Disk Mode performance on iMac (early 2011) models. October 26, 2011 - 3.69 MB
Boot ROM or SMC Version Information: After iMac EFIupdate has successfully completed, your Boot ROM Version will be IM121.0047.B1D
http://support.apple.com/kb/DL1470
For more information about Lion Recovery, please visit http://www.apple.com/macosx/recovery/.
Now, having a backup is/was and always Step #1 before upgrading to going through Boot Camp changes and install. Print out read the guide either from Boot Camp Assistant itself or
http://www.apple.com/support/bootcamp
Apple Boot Camp Assistant sometimes kicks out an error message that is misleading, false, saying you need to perform some update, when there is none and/or not needed (already applied).
Getting the drive to one user HFS volume (Lion Recovery does not count) repaired;
ALL the free space consolidated - contiguous - without fragments - is necessary to carve out a partition for Windows.
By shrinking the HFS volume first, and then expanding back, can work.
But have a backup.
Repair the drive from Lion Recovery
Zap PRAM
Burn incense
Try Boot Camp Assistant and not Disk Utility to create partitions if you are going to put Windows 7 on your system (Vista and XP are not supported by Lion)
The iMac EFI Update will update the EFI firmware on your iMac computer. When your iMac restarts, a gray screen will appear with a status bar to indicate the progress of the update. It will take several minutes for the update to complete. Do not disturb or shut off the power on your iMac during this update.