Direct amp recording - need help

[web]

hi all

for the last 15 years i've been recording my home guitar track pretty simple - guitar-amp-cabinet-mic-mixer-pc
for a certain reason, cabinet has to be omitted for some time so here's the big question - how can I record guitar amp (i use JCM8000 and peavey 5150) STRAIGHT into my mixer?
I guess I have to use some kind of "middleman" between amp and mixer otherwise i might burn everything...so, the big question is WHAT TO USE? My budget for this is about US$600 so any advice will be more then appreciated