The sooner you decide which bachelor-degree granting school you'd like to ultimately attend, the better. Each school has different admission requirements, so be mindful of that when selecting your PSC courses. And keep an eye on application deadlines - typically, you'll need to apply several months in advance of when you'd like to start attending.
Also see the Transferring Credits to a College or University page for links to transfer information for many popular schools in the Illinois area.