The only way to "boost" your internet download speed is by using software that compresses the data. You cannot increase the *actual* speed of the internet connection. This type of software has varying degrees of success depending on what you're downloading. Data that isn't already compressed may download more quickly; files such as .ZIP and .JPG which are already compressed won't download any faster.
"Onspeed" was quite popular for use with dialup connections and they do have a version for broadband which might be worth a try. click here