If your television has RCA audio output ports, you will only need a set of audio cables to connect it to modern speakers. If your TV doesn't have an audio out port but does have a headphone jack, you can use this to connect to computer or MP3-player speakers.
In addition to RCA audio output ports, you might also be able to use a CD or DVD port to connect speakers to your television. Older televisions may not have this option. If your television doesn't have this option and you want to use an RCA cable, look for audio out ports on the cable box.
If the TV has a 3.5-mm headphone jack, you should be able to connect computer or MP3-player speakers without additional equipment. If the TV has the older and larger 1.4-inch headphone jack, you will need a adapter to connect to the 3.5-mm jack of the speakers. This adapter will simply look like a large headphone jack plug sized to fix into the 1.4-inch jack with a space on the opposite end for the 3.5-mm jack to plug into.
If you want to connect computer or MP3 speakers via RCA ports, you will need a different kind of adapter. The adapter will need to have a female 3.5-mm port on one end and standard male RCA plugs on the other.