Firstly,yes
1.Onspeed.The best by far.Gave me 500% boost in surfing(only surfing).Technologu used:- All your data is transferred throug it's super fast servers where is is compressed and sent.THe soft recieves it at your end and sends it to your browser.
End result,text files compressed to 1/10th it's size and images to 1/4th or 1/5th depending upon your settings
www.onspeed.com
7day free trial
*www.onspeed.com/download/trial/ONSPEED_download_trial.zip
2.Artera:-It does work.But no where near as good as onspeed,or as sunny has made it out to be.Technology is similar to onspeed.Can not improve d'load speed.
Other similar software(using similar technique) are propel accelerator and proxyconn.
Another software that does have some effect is ascentive active speed
These softwares effect is much lesser on bband,and are primarily meant for dial-up
Also using fast browsers like opera helps(opera is going to include slipstream web accelerator soon).