The following links will take you to ratings of all relevant gear available for shaman healers. All ratings are listed in terms of "Healing Equivalent Points" (HEP), which represents the relative improvement in total healing output that's obtained by increasing your Healing rating by one.
For an explanation of the math behind these calculations, please read my Comparing Healing Gear series. The specific assumptions used in calculating these ratings are described in Healing Gear: General.
An updated copy (as of Nov. 28) of the spreadsheet I used to calculate ratings is available through FileFront.
For a more general discussion of shaman gear, including enchants and gems, please see Building a Healer: Gear. In addition, changes occurring in 2.3 can be seen in New Gear in 2.3 and New Healing Gear in 2.3.