Place the following in your jQuery mouseover event handler:
$(this).css('color', 'red');
To set both color and size at the same time:
$(this).css({ 'color': 'red', 'font-size': '150%' });
You can set any CSS attribute using the .css() jQuery function.
Or you may do the following
$(this).animate({color:'black'},1000);
But you need to download the color plugin from here.
Nowadays, animating text color is included in the jQuery UI Effects Core. It's pretty small. You can make a custom download here: http://jqueryui.com/download - but you don't actually need anything but the effects core itself (not even the UI core), and it brings with it different easing functions as well.
Source: Stackoverflow.com