changing the oil is pretty easy.
take out the sump plug and drain the oil (or as much as can go) into a suitable container.
use an oil filter removing tool to take off the filter again catching oil in the container.
put on new filter but rub some of the old oil around its rubber seal it helps it to seal.
its possibly best to use a new sump plug and washer(?) as opposed to the old one and put it back in its place.
fill with new oil but do it slowly and keep checking the dipstick cos i cant remember the amount required.
The old oil can be disposed at your council refuse bit or you could take it to a local garage and ask if they will get rid of it for you.
If i have missed anything or anything i have said is wrong someone correct me <img src= "smileys/silly.gif">