It was on my todo list for a long time: configuring pVoice to use different colors and fonts. But now it's done. Starting from the final release of pVoice 2.2, you can define custom colors and fonts.
Some people have problems seeing different combinations of colors, and might need larger fonts. As you can see on this screenshot (http://jouke.pvoice.org/files/colorsandfonts.png), you can make pVoice look prettier