Yesterday, we heard that flash got released (as far as you release something for a jailbreak) and today we now have a simple install from cydia. Just add http://repo.benm.at as a source and search for Frash.
I have not installed it on my iphone 3g because the architecture does not support it and I still have not got around to jailbreaking the ipad, so I have not tested it myself, but based on what I have been reading, its still a bit buggy and does not work with all Flash sites so my takeaway is that we are still not there yet, but its promising.
If there is a flash web tool that you have to use; give it a shot, or you can use CloudBrowse. Also, there is a SBSetting switch for it, so I would recommend keeping it off till you need it. Most of flash on websites are adverts anyway.