Well there is this type of dreamy effect:
http://www.createblog.com/tutorials/download.php?id=391If you want a effect like this:
(original is on the left)

If so, open up the picture you would like, go to
Image> Adjustments > Variations
Change the colors of the image as you would like

Then duplicate your background layer, then go to
Filter > Blur > Gaussian Blur
Set the pixel size to 50px.
Then go back to the layer and set it to overlay.
Hope your using photoshop

If your confused I can write it in to a formal tutorial.