Alex I won't presume if you supply all the information at once next time =) All we can do is guess if you don't give us ALL the information. You've only made a few posts so we don't know you or your background at all, and the average new poster around here is either a college student looking for help on their homework or someone that has no clue what they're doing.
You could put them in series by disconnecting the safety ground on the supplies, this will however cause the case of the power supply to carry a voltage, so you'll have to isolate every power supply from each other and casual contact. Then you can daisy chain the two supplies, I have NO idea what that will do to the voltage stability of the supplies though especially at high currents, I've never seen someone try to do it before (bring a fire extinguisher) as kchristie says use say a 1 ohm power resistor on each output to ballance current.
Two 10 amp supplies will not a 20 amp supply make though, you'll have to derate it somewhat or you'll have stability problems, not to mention you can't just slam a 100amp DC load onto the supply or one or all of the power supplies will go into current limiting mode, which may have nasty effects if you lose only one supply when you have 2 in series and say 5 or more in parallel. Again we can only guess because you've supplied us with no information about the power supplies you have available.
Why such a messy setup? The simplest sollution is since you have a generator is to use a 120 volt AC motor in the first place and a large capacitor to power correct it yourself. That many PC power supplies in series and parallel along with the resistores required to ballance the current is going to be horrdendously ineffecient, if it works at all.