I received an email this week asking how I watermark the photos I post on my blog. Here's the secret: a wonderful website called Picmarkr. This site allows you to resize photos, add the text you want, and then instantly download the marked photos. There are a variety of text options and text placement positions available to get the look you want. You can process up to 5 photos at a time. Best of all, this website offers this service FREE of charge.
If you want to watermark an unlimited number of photos at one time or create a custom watermark template, then the PicMarkr Pro option would be the choice for you. There's a free trial available if you want to test drive it before purchasing.
For bloggers, I can't recommend Picmarkr high enough.
[Disclaimer: I have no association with this website other than the use mentioned in the first paragraph.]