If you love photo mosaics, check out Mosaically, a website that lets you create your own photo mosaics with ease! You don't need any design or editing skills to use the tools on the site. All you do is upload pictures from your computer and/or let Mosaically access your Facebook photos, and these images are used to create the mosaic. You also need to choose one picture of yours that you want to be the "big picture" that your other photos create through the mosaic.
Mosaically offers other fun and useful features, too. For example, you can collaborate with other people where you all upload images together that can be used to create a mosaic. This could be great for a team project at work, etc. You can also take an existing photo mosaic and remix it.
You can use the tools on Mosaically to create, share, collaborate, and remix for free. There are some features of the site that have a price attached to them, such as buying a premium luster print or buying a print-ready download.
I think this is a fun site that is definitely worth exploring if you want to make unique images for print or for the web, for work or just for fun gifts.