You can use the terminal emulator from the market (free). Just don't put it on the sd card.
Put the recovery.img and the flash_image on the root of the sd card.
Then open terminal and type in:
(line #1) su(return) [If using a command Prompt on a PC type in: adb shell (return) instead]
(line #2) mount
_-o
_remount,rw
_-t
_yaffs2
_/system
_/system(return)
(line #3) cat
_/sdcard/flash_image
_>
_/system/bin/flash_image(return)
(line #4) chmod
_755
_/system/bin/flash_image(return)
(line #5) flash_image
_recovery
_/sdcard/recovery.img [or however it's named exactly, on the sd card] (return) If you get a # after typing all that in, continue with the sixth line of code. If you did not, or got an error anywhere, start over.
(line #6) reboot
_recovery(return)
The red underscores are where the spaces should be, do not type them.
(return)=do not type this. Just hit the enter key(the one on the bottom right if in the terminal emulator)
(line #) don't type this in.
If you just need to flash a recovery then skip the third and forth line of the code.
Note: If after typing in su and hiting enter key you loose the keyboard, just hit the menu key and select to toggle soft keyboard.
Here is a link to the flash_image:
flash_image