=== modified file 'bin/addons/base/res/partner/wizard/wizard_spam.py'
--- bin/addons/base/res/partner/wizard/wizard_spam.py	2009-06-08 05:55:05 +0000
+++ bin/addons/base/res/partner/wizard/wizard_spam.py	2010-10-29 12:50:24 +0000
@@ -23,6 +23,7 @@
 import wizard
 import pooler
 import tools
+import re
 
 email_send_form = '''<?xml version="1.0"?>
 <form string="Mass Mailing">
@@ -43,6 +44,9 @@
 def _mass_mail_send(self, cr, uid, data, context):
     nbr = 0
     partners = pooler.get_pool(cr.dbname).get('res.partner').browse(cr, uid, data['ids'], context)
+    type_ = 'plain'
+    if re.search('(<(pre)|[pubi].*>)', data['form']['text']):
+        type_ = 'html'
     for partner in partners:
         for adr in partner.address:
             if adr.email:
@@ -50,7 +54,10 @@
                 to = '%s <%s>' % (name, adr.email)
 #TODO: add some tests to check for invalid email addresses
 #CHECKME: maybe we should use res.partner/email_send
-                tools.email_send(data['form']['from'], [to], data['form']['subject'], data['form']['text'],subtype='html')
+                tools.email_send(data['form']['from'], [to],
+                        data['form']['subject'],
+                        data['form']['text'],
+                        subtype=type_, tinycrm=True)
                 nbr += 1
         pooler.get_pool(cr.dbname).get('res.partner.event').create(cr, uid,
                 {'name': 'Email sent through mass mailing',

=== modified file 'bin/tools/misc.py'
--- bin/tools/misc.py	2010-08-10 09:40:06 +0000
+++ bin/tools/misc.py	2010-10-29 12:48:55 +0000
@@ -39,6 +39,10 @@
     from threading import local
 
 from itertools import izip
+try:
+    from html2text import html2text
+except ImportError:
+    html2text = None
 
 # initialize a database with base/base.sql
 def init_db(cr):
@@ -330,13 +334,7 @@
     if not email_bcc:
         email_bcc = []
 
-    if not attach:
-        try:
-            msg = MIMEText(body.encode('utf8') or '',_subtype=subtype,_charset='utf-8')
-        except:
-            msg = MIMEText(body or '',_subtype=subtype,_charset='utf-8')
-    else:
-        msg = MIMEMultipart()
+    msg = MIMEMultipart()
 
     msg['Subject'] = Header(ustr(subject), 'utf-8')
     msg['From'] = email_from
@@ -364,11 +362,16 @@
     if tinycrm:
         msg['Message-Id'] = "<%s-tinycrm-%s@%s>" % (time.time(), tinycrm, socket.gethostname())
 
+    if isinstance(body, unicode):
+        body = body.encode('utf-8')
+    msg.attach(MIMEText(body or '', _charset='utf-8', _subtype=subtype))
+
+    if html2text and subtype == 'html':
+        text = html2text(body.decode('utf-8')).encode('utf-8')
+        msg.attach(MIMEText(text, _charset='utf-8',
+            _subtype='plain'))
+
     if attach:
-        try:
-            msg.attach(MIMEText(body.encode('utf8') or '',_subtype=subtype,_charset='utf-8'))
-        except:
-            msg.attach(MIMEText(body or '', _charset='utf-8', _subtype=subtype) )
         for (fname,fcontent) in attach:
             part = MIMEBase('application', "octet-stream")
             part.set_payload( fcontent )