I can't help you with downloading movies from the internet, you are on the wrong forum for that type of info and I cannot provide any information on how to do this.
Instructions for converting files are as follows.
This is the software that I've been using recently as it allows me to convert just about anything to anything.
SUPER ©
It's freeware so you don't have to buy anything. (obviously they will try to punt you other products, but if you can't get it from here then download.com or similar will probably have it)
erightsoft downloads - Free software downloads and software reviews - CNET
The gui is quite clunky, however, the options for conversion really make up for this, plus being able to select the "quality" of both audio and video mean that you can really squeeze a lot of movies onto a relatively small space. I've found a typical 1hr show (with Adverts removed) can be reduced down to just below the 100Mb mark with no visible reduction in quality (remember you are going to be viewing it on a 4" screen)
There are also lots of pre-set setting to try and simplify usage.
One trick I have found is make sure you specifiy the output directory for the converted file (right click on the SUPER application and you can set it there)
It really is a little trial and error as far as quality of output goes, however once you find a quality thats right for you, you'll probably never change the setting again. It really depend on the quality of the original file in some instances, i.e. there's no point turning the bit rate and sample rates all the way up if the original file is not of a high quality.
I'm maybe making it sound more complicated that it is, but once you have had a play with the software it is really quite simple to use.
let me know how you get on. I have pretty limited access over the next few days so apologies in advance if a little slow getting back to you.