Netbooks are all the rage at the moment, with Asus predicting that it will sell 5 million of its Asus Eee PC netbooks by the end of this year. However, one of the tricky aspects of netbooks is that they have much more limited hardware resources than larger, traditional notebooks. For that reason, it makes sense to put applications on your machine that are both lightweight and powerful. The good news is that many of the best choices are free.