Presentation posterboard

[cw42]

I have to display a project, and need to put images and text onto a big piece of posterboard, or one of those tri-fold posterboard things. I'd rather not print out pieces of paper, and glue/tape it to the posterboard. So, how would I go about making this? Would I do something like mock it up in Photoshop, and take it somewhere to get it printed? (btw where can I get posters printed?)

Thanks.