Manufacturer Warranty Questions

I'm currently working with a couple of vendors whose products offer manufacturer warranties. I am a fully registered business with local, county, state, and Federal. I sale mainly on eBay. What steps do I need to take to make sure my customers can take advantage of the warranty. Is it in the invoicing/sales receipt process? Also do I need to include UPC and Bar Code information?

I would leave that in the hands of the customer. But You will have to address the companies. If your buying stock from a retailer the warranty is to be considered void and you should remove all warranty cards.

I personally offer a squaretrade warranty program with every electronic item I sell.