Hi and welcome!
I don't know about Walgreen, the best thing would to contact them. However, there are some things that are good to know before trying to stitch pictures.
Stitching is a somewhat sensitive operation, and I wouldn't trust a store to do it for me, because I would loose the ability to fine-tune and I wouldn't have any warranty that I would be satisfied with the result.
Most camera brands offer a stitching program with their bundled softwares, and these programs usually work well enough. Many cameras also have a built-in Stitch or Panorama mode, which could help you frame your pictures.
Some things to remember:
1-when taking multiple pictures, ALWAYS make sure the frames overlap by at least 30% so the software will be able to superimpose the various images
2-try to keep the camera on a fixed spot, and rotate it. Do not hold it at arm's length and swivel your whole body, the output could very well become distorted (curved horizon, for instance). A tripod is a big bonus here.
3-be sure to include some vertical landmarks in your frames so the stitching is easier. For instance, a stitching of the sea line would not deliver good results. A stiching of mountains would be much easier.
4-Try to avoid having very near and very far objects in the same frame. The stitching software could have problems superimposing all the images.
If your camera allows it, lock the exposure. Otherwise, your various images could have different brightness settings and this would lead to poor stiching.
As you can see, it's not a fuly automatic process. Once you have experimented a bit, however, it becomes fairly easy. My last stitching was a 400 feet waterfall made of 9 images, and I printed it on a 1x3 feet photo paper. It's one of the best pictures I've made.
You can find additional information here:
http://www.digicamhelp.com/camera-features/shooting-modes/panorama.php
