MAGENTO - setup 2nd store,currency,cart

I have a project where i will need two stores run by one magento installation, sharing one domain with the stores showing up under two subdirectories. Those two stores should have different store views, checkouts and currencies. My Requirement is that it has to be absolute stable !!! I already set up the different store views, language, style templates but couldn't do the rest on my own ... if you need more information i like to send you the links of what i have done so far ?