Ive been playing with Sitepal, which allows you to add a talking avatar to your own site. Too expensive for me (between $10 and $50 per month, depending on functionality) but a good example of what is available.
According to its website, Sitepals avatars come with a range of shapes and voices, can read from text, and even offer AI capabilites.
Though when I tried this I wasnt too impressed. The avatar wouldnt win the Loebner prize, and had an endearing habit of saying “br slash” at the end of each line. (Though they do claim that you can train the system.) The lip synch is a bit crude, but the avatars move convincingly, blinking and making small movements even when theyve lost focus.
The pricing is clearly aimed at sales uses rather than personal sites or blogs. As a sales tool I suspect it would work by novelty value – but if everybody had one it would soon be seen as an annoyance.
I really like this one. If money was no object Id put one on this site, at least for three months or so. If I chose the voice called Simon (cultured, English, professional) and the face called Tom (handsome, dynamic, young executive type) youd all assume that was me after a while, wouldnt you?