1 - Its available on ebay india and in local ink refilling shops for lesser price. The CISS system is according to cartridge used in the printer. example many hp printers have those 1 black and 1 colour cartridge, wehereas some have individual colour cartridges.
2 - Ciss is an ink tank system. there are tubes coming out from bottom of the ink tanks and these have some small plastic regulator at their other end. you need to peel the sticker of the top of the ink cartridge to get access to the ink filling hole. drill a small space with provided drill bit in the sponge inside the cartridge and then put regulator on top of the hole. There is a stopping mechanism (which pinches the tubes tight) somewhere near the ink tank. If this is opened, ink flows to the cartridges normally. Ink tanks are always kept at a lower height than the printer and the ink cartridges inside. You need to fit the tubes coming from printer properly so that the ink cartridge can glide normally without restriction or tugging on the ink tubes. You also need to take care so that the door of cartridge compartment closes properly after fitting the tubes.
3 - Inks are available everywhere at around 400-600 for 4x 100ml ink bottles. each tank in ciss system holds 100ml ink. inks are available in both dye based and pigment based varieties and you need to make sure which type of ink your cartridge uses. Hp uses pigment inks mostly (like my aio does), but just check twice to be sure. Some say dye based ink should be used in ciss systems since they dont clog the tubes.
Before you ask, I haven't put a ciss system for my hp aio 4050. i used to just manually fill ink with a syringe in the inks till now, which as i found out is tedious and does not work everytime. plus i get my hands coloured every time with ink spots.
even i'm thinking of getting one for my printer now. just fed up with hp's over priced cartridges which just dont last even 40 pages for a 500 rupees cartridge. cartridge has 150 pages written on it. wonder how they test them. Only thing bothering me is my ink cartridges use pigment ink whereas its recommended by almost everyone to use dye based ink in ciss. so i was unsure of taking that step since it would mean a loss of money on the whole system along with cartridges and inks too.
Links -
http://www.ebay.in/itm/EMPTY-CISS-F...rinters_Scanners_Supplies&hash=item3cd01b0d81 (see list of supported printers) no ink included
http://www.ebay.in/itm/CISS-FOR-HP-...rinters_Scanners_Supplies&hash=item3cd094a512 (inks included)
edit: installation (not similar kit but you can get a fair idea)
http://www.youtube.com/watch?NR=1&feature=fvwp&v=9A8rYDPezd0
second one is in spanish but i guess its self explanatory.
only inks -
http://www.ebay.in/itm/RI07-REFILL-...rinters_Scanners_Supplies&hash=item2ec6f4ef5a
http://www.ebay.in/itm/CISS-INK-FOR...rinters_Scanners_Supplies&hash=item3cd03b4e17