When you have a large digital image, let's say 6 megapixels or 10 megapixels, and you downsize it to post on the web, it is totally normal to have to sharpen it. The process of downsizing that huge image adds some softness. Using a bit of unsharp mask in Photoshop is nothing out of the ordinary.
If the images still look blurry, then it probably has to do with your technique when you took the photo. As has been stated before, using a tripod makes a huge difference.