Overseas employess

Hi,i have a US business and recently i started hiring people from outside of the USA (india,mexico,philphiness)

I was wondering if there's any laws or regulation i need to follow or i can just pay them directly with Paypal ?

That depends really... are you hiring them as freelancers? Then you can pay them per paypal for "services rendered".
If you're hiring them on a more permanent basis, you'll need to check out their countries laws regarding salaries etc... some countries require YOU to make sure that taxes are paid etc etc..