http://psxemulator.gazaxian.com/ is the best damn emulator out there atm. v1.8 just got released. No plug ins required just unzip and run....well you have to get a psx bios but you should be able to find if you look around. The "rom" or rather the disc image you can find on most torrent sites. PM me if you need any help.
EDIT: By best i mean it runs pretty much all games just like a PSX would. There is another emulator out there called epsxE that is good but its very handy to use if you want to tweak with the graphics. Some of those psx games clean up real nice when you run them on a modern graphics card.
But you wont have to worry about that if all you want to play is Tactics.