Personalize Text Wallpaper
If all you want is static text that doesn't change in any way, then by far the easiest way is to open your wallpaper image in an imaging editing program either on a PC (something as simple as Windows Paint would do) or on the phone (search the Android Market for something like "image editor" or "photo editor" and you should find lots of apps that can do this like PicSay or Pho.to Lab) and add the text straight onto the picture.