import arcpy

def FindField(fc,myField):
        fieldList = arcpy.ListFields(fc)
        for field in fieldList:
            if str.lower(str(field.name)) == str.lower(myField):
                print "    " + fc + " contains fieldname: " + myField

def FindField2(fc,myField2):
        fieldList = arcpy.ListFields(fc)
        for field in fieldList:
            if str.lower(str(field.name)) == str.lower(myField2):
                print "    " + fc + " contains fieldname: " + myField2


myField = "RuleID"
myField2 = "Override"
dir = r'D:Testgdb'
arcpy.env.workspace = dir

gdbList = arcpy.ListWorkspaces('*','FileGDB')

for gdb in gdbList:
    arcpy.env.workspace = gdb
    datasetList = arcpy.ListDatasets('*','Feature')
    fieldList = arcpy.ListFeatureClasses()
    for fc in fieldList:
        print arcpy.env.workspace,fc
        print "Searching root level Featureclasses..."
        print "  Searching " + fc
        FindField(fc,myField)
        FindField(fc,myField2)

    for dataset in datasetList:
        arcpy.env.workspace = dataset
        fieldList = arcpy.ListFeatureClasses()
        for fc in fieldList:
            print arcpy.env.workspace,fc
            print "  Searching Featureclass... " + fc
            FindField(fc,myField)
            FindField(fc,myField2)

D:TestgdbRT_FactGeology_Qld_25K.gdb Rio_FactGeology_Qld_L
Searching root level Featureclasses...
Searching Rio_FactGeology_Qld_L
Rio_FactGeology_Qld_L contains fieldname: RuleID
Rio_FactGeology_Qld_L contains fieldname: Override

D:TestgdbRT_Roads_Qld_25K.gdb Rio_Roads_Qld_L
Searching root level Featureclasses...
Searching Rio_FactGeology_Qld_L
Rio_Roads_Qld_L contains fieldname: RuleID
Rio_Roads_Qld_L contains fieldname: Override

Runtime error
Traceback (most recent call last):
File "<string>", line 31, in <module>
File "<string>", line 6, in FindField
UnicodeEncodeError: 'ascii' codec can't encode character u'xf3' in position 7: ordinal not in range(128)