Aside for the EXCELLENT information on localization within XMOD, much of the information on localization and .resx files as it pertains to DNN is 'scattered' around web... Adding some clarity somewhere in the XMOD documentation will help avoid the MANY hours it took to figure out...

#1
In DNN if you wish to localize text you MUST have a 'default' language .resx file within your form and template folders.
For Example - If the default DNN language is us-EN, DNN looks for xmod_form.ascx.resx NOT xmod_form.ascs.en-US.resx as one might assume.

#2
.resx file get COMPILED and any changes are NOT reflected until you restart the DNN site. ( Clearing the Cache under the HOST menu AND "recycling" the App Pool in IIS also works...

Hope this can help someone...