diff --git a/composer/schema/field.py b/composer/schema/field.py
index a22aabd..f26527b 100644
--- a/composer/schema/field.py
+++ b/composer/schema/field.py
@@ -25,11 +25,13 @@ $Id$
 from zope.interface import implements
 from zope import schema
 
-from cybertools.composer.base import Component, Element, Compound
-from cybertools.composer.base import Template
+from cybertools.composer.base import Component
+from cybertools.composer.schema.interfaces import IField
 
 
-class Field(Component, schema.Field):
+class Field(Component):
+
+    implements(IField)
 
     def __init__(self, name, title=None, renderFactory=None, **kw):
         assert name
diff --git a/composer/schema/interfaces.py b/composer/schema/interfaces.py
index 1046ac9..7a1d7ea 100644
--- a/composer/schema/interfaces.py
+++ b/composer/schema/interfaces.py
@@ -22,6 +22,51 @@ Schemas and Fields.
 $Id$
 """
 
+from zope import schema
 from zope.interface import Interface, Attribute
+from zope.i18nmessageid import MessageFactory
+
+from cybertools.composer.interfaces import ITemplate, IComponent
+
+_ = MessageFactory('zope')
 
 
+class ISchema(ITemplate):
+    """ Represents an ordered sequence of fields.
+    """
+
+    fields = Attribute('The components the schema is built up of. '
+                'Should be a sequence of IField objects.')
+
+
+class IField(IComponent):
+    """ May be used for data entry or display.
+    """
+
+    name = schema.ASCII(
+                    title=_(u'Fieldname'),
+                    description=_(u'The internal name of the field'),
+                    required=True,)
+    title = schema.TextLine(
+                    title=_(u'Title'),
+                    description=_(u'The title or label of the field'),
+                    required=True,)
+    description = schema.Text(
+                    title=_(u'Description'),
+                    description=_(u'A more lengthy description of the field'),
+                    required=False,)
+    fieldType = schema.Choice(
+                    title=_(u'Field type'),
+                    description=_(u'The type of the field'),
+                    required=True,
+                    default='textline',
+                    values=('textline', 'textarea', 'date'))
+    defaultValue = schema.TextLine(
+                    title=_(u'Default'),
+                    description=_(u'Value with which to pre-set the field contents'),
+                    required=False,)
+    required = schema.Bool(
+                    title=_(u'Required'),
+                    description=_(u'Must a value been entered into this field?'),
+                    required=False,)
+
diff --git a/composer/schema/schema.py b/composer/schema/schema.py
index 71ec87f..7526ce4 100644
--- a/composer/schema/schema.py
+++ b/composer/schema/schema.py
@@ -26,10 +26,13 @@ from zope.interface import implements
 
 from cybertools.composer.base import Component, Element, Compound
 from cybertools.composer.base import Template
+from cybertools.composer.schema.interfaces import ISchema
 
 
 class Schema(Template):
 
+    implements(ISchema)
+
     def __init__(self, *fields):
         super(Schema, self).__init__()
         for f in fields:
diff --git a/organize/service.py b/organize/service.py
index e929937..0ee99c5 100644
--- a/organize/service.py
+++ b/organize/service.py
@@ -37,7 +37,7 @@ class Service(object):
 
     implements(IService)
 
-    def __init__(self, seats=-1):
+    def __init__(self, capacity=-1):
         self.capacity = capacity
         self.registrations = []