I have made my CV using Photoshop CS5.1 (3 separate files) and need to convert it to a single PDF file. I've done it before using a free download but can't remember what it was...does anybody know? Or is there another way this can be done?
You can do it in photoshop.
From the top menu ( doesn't exist in cs6 anymore ): File > Automate > PDF Presentation..
In the PDF Presentation window:
..and then the Save abobe PDF window comes up, where you can define the pdf settings and then save it.
If it is not that obvious, every separate file will be put in their own pages in the pdf document.
Another way to do this would be in Adobe Acrobat Pro.
To combine multiple files into one pdf in Acrobat Pro: File > Combine > Merge files into single pdf
( You can also change page locations, delete pages, add pages etc... )
In OSX, you can do this with Preview.app. Open one PDF, drag another into the thumbnails panel to add additional PDF files. (FWIW, PhotoShop isn't the right tool for creating a resume)