diff --git a/app/views/account/login.rhtml b/app/views/account/login.rhtml
index a9cf6da..0d8f9d6 100644
--- a/app/views/account/login.rhtml
+++ b/app/views/account/login.rhtml
@@ -4,7 +4,9 @@
 
 <% labelled_form_for :user, @user, :url => { :controller => 'account', :action => 'login' } do |f| %>
 
-<%= display_form_field(_('Login'), text_field_tag(:login) ) %>
+<%= display_form_field(_('Login'),
+    text_field_tag(:login, nil,
+    :onchange => 'this.value = convToValidLogin( this.value )') ) %>
 
 <%= display_form_field(_('Password'), password_field_tag(:password) ) %>
 
diff --git a/app/views/account/login_block.rhtml b/app/views/account/login_block.rhtml
index 3ef5b6f..a321fc9 100644
--- a/app/views/account/login_block.rhtml
+++ b/app/views/account/login_block.rhtml
@@ -8,7 +8,9 @@
     <% labelled_form_for :user, @user,
        :url => { :controller => 'account', :action => 'login' } do |f| %>
 
-      <%= display_form_field(_('Username'), text_field_tag(:login) ) %>
+      <%= display_form_field(_('Username'),
+          text_field_tag(:login, nil,
+          :onchange => 'this.value = convToValidLogin( this.value )') ) %>
       <%= display_form_field(_('Password'), password_field_tag(:password) ) %>
 
       <% button_bar do %>
diff --git a/app/views/account/signup.rhtml b/app/views/account/signup.rhtml
index 22dc57b..b366537 100644
--- a/app/views/account/signup.rhtml
+++ b/app/views/account/signup.rhtml
@@ -3,7 +3,9 @@
 <%= error_messages_for :user %>
 <% labelled_form_for :user, @user do |f| -%>
   
-<%= f.text_field :login %>
+<%= f.text_field :login,
+                 :onchange => 'this.value = convToValidLogin( this.value )' %>
+
 <%= f.text_field :email %>
 <%= f.password_field :password %>
 <%= f.password_field :password_confirmation %>
diff --git a/public/images/icons-app/gravatar-minor.gif b/public/images/icons-app/gravatar-minor.gif
new file mode 100644
index 0000000..c7d023e
Binary files /dev/null and b/public/images/icons-app/gravatar-minor.gif differ
diff --git a/public/images/icons-app/gravatar-thumb.gif b/public/images/icons-app/gravatar-thumb.gif
new file mode 100644
index 0000000..c33b311
Binary files /dev/null and b/public/images/icons-app/gravatar-thumb.gif differ
diff --git a/public/javascripts/application.js b/public/javascripts/application.js
index 7af4e6b..b724343 100644
--- a/public/javascripts/application.js
+++ b/public/javascripts/application.js
@@ -25,6 +25,20 @@ function focus_first_field() {
   }
 }
 
+/* * * Convert a string to a valid login name * * */
+function convToValidLogin( str ) {
+  return str.toLowerCase()
+            .replace( /á|à|ã|â/g, "a" )
+            .replace( /é|ê/g,     "e" )
+            .replace( /í/g,       "i" )
+            .replace( /ó|ô|õ|ö/g, "o" )
+            .replace( /ú|ũ|ü/g,   "u" )
+            .replace( /ñ/g,       "n" )
+            .replace( /ç/g,       "c" )
+            .replace( /[^-_a-z0-9]+/g, "" )
+}
+
+
 /* * *  Template Box Size Help  * * */
 function resizePrincipalTemplateBox() {
   var box1 = $$( "div.box-1" )[0];
--
libgit2 0.21.2