There are hundreds upon hundreds of free fonts available for download. Once you find your favs, you must insert them into your computer's font folder in order to access them. Once they are plugged in they will work on any program on your computer that uses fonts including photoshop. You can add an additional layer in photoshop to add text to any image.
I use Windows 7. If you use Windows Vista, XP, or Mac OSX, click here for a tutorial.
For Windows 7, locate your control panel. Then select appearance and personalization.
You will see these choices (below). Click on fonts.

It will look something like this.

Just copy and paste your unlocked font into this location.
Tip: I download fonts and then extract them to my desktop for easy access and retrieval. Once they are plugged into my font folder I delete them off my desktop.
Here are some of my favorite fonts.

Download 1942 report here.

Download CK jot here.

Download CK Ali's Hand here.

Download Depressionist Three here.

Download WW Flakes here.

Download VT Portable Remington here.

Download Splendid 66 here.

Download 2Peas GGs Love Me here.

Download Pea Kevin & Amanda here. Plus hundreds of others from her here. You can even choose to download her entire collection here.
Submit your own handwriting and have her convert it into a font for you. She shares new fonts every Friday. A fabulous site to bookmark!
I hope that you enjoy playing with some of these fonts. They can certainly transform any picture or scrapbook page!
Have a great week!