Alternatives for a few Windows programs
 

I'm looking for something similar to these pieces of software to use in Linux (Suse 9.2).

CpuIdle:
Cools down the cpu when it's idle.

DU Meter:
Shows download/upload speeds in a graph that can be opened from the system tray, also keeps data transfer statistics.

Protowall/Windows HOSTS file:
Ip blocking. Preferably some solution that can be switched on and off conveniently.

If anyone can help me out, I'd be happy. I'm new to Linux so I might not understand complicated answers. :) I have googled, found nothing for the first two but I found several programs for ip blocking and I'm not sure which one I should choose.

For cooling the CPU I'm not sure what programs are out there but the newer kernel versions have the option of CPU frequency scaling which can reduce the voltage in the processor while it is idle.
For the second software you can use something like GKrellM: http://members.dslextreme.com/users/.../gkrellm.html. It has lots of other statistics to show.
IP blocking is usually done using NetFilter (also reffered to as iptables even if it's not entirely correct). You can do much with a proper firewall. Some instructions can be found at http://www.faqs.org/docs/iptables/index.html

Thanks for the help.