Use google like was said, and/ or wordtracker free to expand out. Paste into notepad to erase html. Then post into OpenOffice or Excel to organize the lists.
Once you have a nice long list of keywords, you can work on generating an even longer list by creating a separate keyword for pretty much every permutation of the keywords that you can think of. You can do that fairly easily in Excel (or OpenOffice Calc), but you can also use this free tool to make it a little faster:
SplutWeb: Keyword Permutation Tool
You don't have to use notepad in order to remove HTML, you can just right click in excel and select "Paste Special", then use "Values" option.
Good luck
Good to know. You learn something new everyday.