Hey guys I hope that this question has been asked so many times.Live in India & I am new to Raspberry Pi hack. All I have is an old laptop of mine, HP DV6700 to be precise. It doesn't have an HDMI port (It has a VGA port, some long hdmi like port & a S-video port) & I don have a TV which has an HDMI port. I want to connect my Rpi to my laptop to use it. What are the things that I should buy? Thank you.
You could use VNC on your RPi and on your laptop to have a remote access visually. Just search the internet for a good VNC client, I personally use TightVNC.
Also if you'd prefer to use the Remote Desktop Protocol (this could be useful if your working at a company that blocks VNC's ports, most companies at least allow outgoing RDP connections) then use XRDP on the RPi and just normal Remote Desktop on your windows machine.
- An ethernet cable. Apparently, the Pi has a built-in feature called auto-MDIX that allows you to directly connect it to your laptop with an ethernet cable, no router/hub/switch/modem required.
- A mini-usb cable. Of course, chances are that if you have a Pi and are planning to use it, you will have this already, but I am including it just for completeness' sake.
- A power source. The Raspberry Pi Foundation does not recommend using your laptop (or desktop, for that matter) as a power source (500-700 mA is a lot to source from a USB port intended for data), so it would probably be best to use a dedicated power supply. When shopping, look for a USB power supply that sources at least 700 mA for the model B and 500 mA for the model A at 5V.
Finally, this link gives you everything that you need to know to start getting the Pi's GUI running on your laptop using VNC (Linux and OS X only, if you don't have Linux then grab Ubuntu and install it on your laptop).
As others wrote, ssh is probably the simplest you can do. If you run an X server on your laptop, you get graphics, too. But it will not be accelerated by the graphics hardware of the PI, I think. The hardware you'll need to buy are: 2 Ethernet cables and a switch, or one cross-over Ethernet cable. Maybe one normal Ethernet cable works, too. If you've got a router for internet access, maybe you can use that instead of the switch (if it has a builtin switch and multiple ethernet ports).
Well since the question is "What to buy?" here's one answer: Get a TV card (or a dedicated video capture card, but TV cards are more common) for the laptop with S-Video input. Such cards exist in USB, PCMCIA and ExpressCard formats and will allow the laptop to capture input from S-Video and display it on its screen. The main (and possibly only) advantage of this method compared to methods shown in other answers is that other devices with S-Video output could use laptop's screen too.