Dude bhaisahaab ... seriously.. search a bit and you`ll know, not that convoluted process. Anyway outline..
1. Open account with PPO / HGS / SnS (Paid i guess)
2. You `ll get a US shipping address.
3. Buy from Ebay (any other site) get it shipped on address you get in step 2
3a. You`ll need mostly a paypal account, some seller accept paypal linked to International CC, some don't.
3b. Some seller only ship to confirmed address, that is address linked to paypal billing, so you wont be able to buy from such sellers.
4. Once your package reaches the service chosen in step 1, process varies with each forwarder. HSG lets you consolidate multiple packages, you`ll have to pay only shipping before package is dispatched, customs is collected on delivery. You can also control when is package shipped to you. PPO nowadays provides estimated customs + shipping as soon as package leaves US, you have to pay before you get the shipment. Never used iShop / SnS et. al.
5. Any other doubt, search