Index: app/helpers/application_helper.rb
===================================================================
--- app/helpers/application_helper.rb   (revision 4260)
+++ app/helpers/application_helper.rb   (working copy)
@@ -591,7 +591,7 @@
   #  Forum messages:
   #     message#1218 -> Link to message with id 1218
   def parse_redmine_links(text, project, obj, attr, only_path, options)
-    text.gsub!(%r{([\s\(,\-\[\>]|^)(!)?(attachment|document|version|commit|source|export|message|project)?((#|r)(\d+)|(:)([^"\s<>][^\s<>]*?|"[^"]+?"))(?=(?=[[:punct:]]\W)|,|\s|\]|<|$)}) do |m|
+    text.gsub!(%r{([\s\(,\-\[\>]|^)(!)?(attachment|document|version|commit|source|export|message|project|user)?((#|r)(\d+)|(:)([^"\s<>][^\s<>]*?|"[^"]+?"))(?=(?=[[:punct:]]\W)|,|\s|\]|<|$)}) do |m|
       leading, esc, prefix, sep, identifier = $1, $2, $3, $5 || $7, $6 || $8
       link = nil
       if esc.nil?
@@ -634,6 +634,10 @@
             if p = Project.visible.find_by_id(oid)
               link = link_to_project(p, {:only_path => only_path}, :class => 'project')
             end
+          when 'user'
+            if u = User.find_by_id(oid)
+              link = link_to_user(u)
+            end
           end
         elsif sep == ':'
           # removes the double quotes if any
@@ -676,6 +680,10 @@
             if p = Project.visible.find(:first, :conditions => ["identifier = :s OR LOWER(name) = :s", {:s => name.downcase}])
               link = link_to_project(p, {:only_path => only_path}, :class => 'project')
             end
+          when 'user'
+            if u = User.find_by_login(name)
+              link = link_to_user(u)
+            end
           end
         end
       end