You might want to try Naomi as I know there are some on this forum who use it successfully. Please read the whole page and especially … Other versions/plugins … as there are many ways to use this helpful and free program. You can find it at the link below …
Also if there is a specific site you would like to block you can enter the site in the Web Shield URL Blocking. You can also use URL blocking to block certain types of files you may encounter online, for example due to the WMF exploit people would type *WMF in the URL Blocking part to block all WMF files.
Same here: Naomi works fine together with Avast!
If you don’t like it, you might try K9.
K9 can be obtained here: http://www.getk9.com
But if you want to keep things simple I suggest you try Naomi since no configuration is needed (or possible) with this one.
If you want to be able to fine-tune things a bit, you can try K9.
After reading Fasts’ post I thought I would check out K9. I have to admit it is far better than Naomi in my opinion but, that depends on your preferences
As Fast said it is more configurable and you choose exactly what you want to be blocked from the categories available - this is not possible with Naomi.