First of all you must know that almost all files of the download except pics are posted on rar or zip format. this is an compressed type of format and you can put normal files like .sis or .jar in a single .rar or .zip file.

Tn order to open these files you must have WINRAR or WINZIP installed on your computer. however i advise you to install winrar because its the best one.

The process to get the files you want from the rar file is very simple:
you just open the rar file, right click on the file you want to extract and choose "extract to specified folder". then choose the folder which you want the file to be placed in.

OR you can just drag the file to the folder you want to place the file in your pc but you must have that folder opened on the explorer.
select all files on the rar file and do the same process if there is more then one file on the .rar file.

Then all you need to do is select the .sis or .jar file (or any other) and transfer it to your phone through the methode you wish (bluetooth, infrared, cable)

But there is another way to do this. the methode i have shown above is for people who use the pc. for people who use their phone to download files you can also use a special app called ZIPMAN.

This app is very simple to use. just send the .rar file to your phone and you can extract the files you want right there on your phone, with this app, not having to use the pc.

Just try it...