http://ausiellofiles.ew.com/2008/12/ask-ausiello--1.htm...roes%2C%27+and+More!

Half way down. This is the same site I found the first new of her first appearance on the show. Feb 20th

Awesome news!

That are great news! can't wait to see it!

BACK TO THE PSYCH WARD
by Zach Oat January 8, 2009 11:08 AM

America is going crazy over the fake psychic who solves crimes! ...Except they've been going crazy about this guy's show for three seasons already. USA's detective comedy Psych returns on Friday with new episodes, and we got the chance to talk to stars James Roday (Shawn) and Dulé Hill (Gus) about what's coming up in terms of romances, guest stars and possible references to a certain other psychic investigator.

[...]

Any more guest appearances we can look forward to before the end of the third season?

Roday: Ted McGinley came up, and his hair is just as ridiculously awesome as it ever was. Mykelti Williamson came up -- he's playing a quarterback, which for me it was like it might as well have been 1986. I was in the theater watching Wildcats with popcorn. Who else did we have? Mackenzie Astin, Justine Bateman... We have a return appearance from Rachael Leigh Cook. Yeah, read into that what you will. And let's see, we're forgetting... oh, Jonathan Silverman, who was one of the nicest guys in the business that you will ever meet.

Hill: He likes to be called Johnny Silver.

Roday: Johnny Silver, the Streak.

Between Shawn hooking up with Gus' sister in the Christmas episode this year, him getting friendlier with Juliet and the return of Rachael Leigh Cook's character, are there any plans for a substantial romance on the show?

Roday: You know what, I think you might just see something like that happening sooner rather than later. I mean, the idea of Shawn trying to negotiate a relationship with a woman is brand-new territory. I have no idea how it's going to go, but I do have a feeling that we're going to sort of scratch at something like that, as you'll see, if you can make it to the fifth season. If I were to list five options -- E being all of the above, hello? -- Juliet would be in there and Abigail, which is Rachael Leigh Cook's character, would be in there. But, you know, we might throw you a couple of curve balls along the way, too.

[...]

Catch the return of Psych this Friday, January 9, at 10pm on USA.


Source.

Thx Quel!
I would like to see her on a regular basis in Psych. I think she would fit in great in that show.