Querying XML Data from a table

Hi,

I was wondering what the easiest way is to select/extract data from XML. Its rather confusing and I have been getting a bit confused with how to do this. I need to be able to select/extract the data from XML and also write update statements to update certain bits of the XML data when I want to.

Details of the XML can be found below.

<QuickReindexOptions><FragmentationLow>5.00</FragmentationLow><FragmentationMedium>30.00</FragmentationMedium><PageCountLevel>1000</PageCountLevel><MaxDegreeOfParallelism>0</MaxDegreeOfParallelism></QuickReindexOptions>

Also, what about if the data is not numeric like the below.

<Options><FragmentationMediumAction>INDEX_REORGANIZE,INDEX_REBUILD_OFFLINE,INDEX_REBUILD_ONLINE</FragmentationMediumAction></Options>