CS4 is actually a really good program! {I prefer it to PSP}
If you just want to try it out before investing in it, you can download free kits from here:
Digital Scrapbook Freebies - DigiScrapDepot.com
I make all of my pages 3600x3600 {12x12}, 300 dpi. You can always downsize later.
I suggest checking out some galleries {you can even look at pages in The Love Shack subforum} and lift a page or two to get comfortable with the program and scrapping.