The 2800+ Barton chip that you have is already factory unlocked, you just need to change the multiplier in the bios, that is, if your Soyo board allows it. If not, search for a newer (or user-hacked) bios that allows you to change it. I don't know much about Soyo boards, though, so I'm not certain it's possible...
You can hard-code the multiplier with the bridges... but do you really want to do that on a 2800+ barton? I'd rather increase the fsb personally... unless your ram is holding you back severely (which, considering it's crucial pc2700, might be the case).
Hope that helps! Good luck!
Methusela