Check out the winning entry to a contest for creating the best Flash presentation about the problems of Bush’s plans for social security. Part of the MoveOn.org PAC. Needless to say, you need Flash to view this.
There were a couple of really interesting points in this thing, but I think the best one is about the cap. Social Security is 6.2% of your salary for the first $90K, for up to something like $6,000 a year. The implication of this is that for folks who make more than $90K, especially people who make a lot more than $90K, they pay a lot less of a percentage of their salary for Social Security than, say, me.