Assuming you have Adobe Audition or Cool Edit, you MIGHT be able to remove a word or two by going into the stereo panning options and reversing the polarity of one channel. If the vocal is dead-center and there's no stereo reverb, the word should (at least mostly) disappear.
Occasionally I've used a combination of tricks: preserve everything below about 200 Hz as the original stereo file, then sum-out the vocals, then low-pass filter if needed to get rid of vocal "smear" (in which case an original stereo file of everything over about 6 or 8 Khz will be needed)... if that isn't enough, sometimes I'll go ahead and reverse all or part of where the offending word was.
As mentioned above, sometimes you can paste from another part of the song (grab a beat from the instrumental intro, etc) or echo a phrase right in beat "...but she ain't messin' with no broke / broke..."
If all else fails, sound effects can be used effectively (or for comic relief!).

I took Casey Casem's rant about doing a dead dog dedication out of an uptempo record and replaced one word with a slower, lower pitched doorbell and the other word with a faster, higher pitched doorbell. If anything, it sounds funnier now than if I'd left it alone. ;D
The free Audacity should be able to do similar tricks, I suspect.
Good luck with this; I was working at an R&B station when Snoop Dog hit... and we had NO digital editing. The radio edit wasn't clean enough for my boss, so I ended up in the production studio with a 4-track and the instrumental, punching back and forth for a live edit / dub to cart. Aarugh! I don't miss those days. :