Because you're using a standard definition TV your laptop resolution will be pretty low. It depends on the TV but you're probably talking 640x480, which is gonna make movies look like shit. They'll be watchable for sure, but you should be prepared to accept a noticeable downgrade in quality.
This is an S-Video input port:
If your TV has one of those that'll be your best bet, quality wise, compared to some other more primitive connections. You can buy cables which will input to S-Video and output from pretty much anything, such as S-Video Out, VGA, DVI or whatever. You can also buy separate adapters for the ends of the cables if you find you've bought the wrong one.
This laptop has a VGA output port:
You can buy a VGA to S-Video cable, and that should do the job. You can get cables which have the audio component cables included on them, usually as three separate coloured connectors (red, white and yellow). Even an S-Video RCA cable, which is an old standard, will suffice if you're using a SDTV. If your TV is quite old you'll most likely have to go with the RCA cable anyway. If you have the instruction manual for the TV handy it should give you the specifications in the back, including the kinds of connections its capable of making.
I'm somewhat new to this stuff myself, so I'll play it safe and refer you to a few websites which are more specific:
[This site lets you select the various connections you'll be using and will advise you on which cable you'll need]
It might be easier investing in a DivX or similarly capable DVD player, preferably one with USB input so you can hook up an external Hard Drive (assuming the movies you wanna watch are downloaded .avi files). You can get these kinds of devices in the UK for as low as £35!
You can also buy dedicated devices which do little else but play media files through your TV, and some even let you browse YouTube and the like. Examples:
Get one of those for your movies, buy a handheld poker game and spend the other $350 on a medium-quality hooker.