Something

mysql> select id, url, memc_set(concat('feeds', md5(url)), url) from feeds;
+----+-------------------------------------------------------+------------------------------------------+
| id | url                                                   | memc_set(concat('feeds', md5(url)), url) |
+----+-------------------------------------------------------+------------------------------------------+
|  1 | http://feeds.feedburner.com/littlegreenfootballs/Ilds |                                        0 | 
| 11 | http://del.icio.us/rss/jacomien                       |                                        0 | 
| 21 | http://del.icio.us/rss/tags/rmj20                     |                                        0 | 
| 31 | http://www.jihadwatch.org/index.rdf                   |                                        0 | 
| 41 | http://www.connotea.org/rss/user/rmj20                |                                        0 | 
| 51 | http://devblog.grazr.com/?feed=rss2x                  |                                        0 | 
| 61 | http://feeds.feedburner.com/littlegreenfootballs/kyeH |                                        0 | 
+----+-------------------------------------------------------+------------------------------------------+
7 rows in set (0.00 sec)

mysql> select url, memc_get(concat('feeds', md5(url))) from feeds;
+-------------------------------------------------------+-------------------------------------------------------+
| url                                                   | memc_get(concat('feeds', md5(url)))                   |
+-------------------------------------------------------+-------------------------------------------------------+
| http://feeds.feedburner.com/littlegreenfootballs/Ilds | http://feeds.feedburner.com/littlegreenfootballs/Ilds | 
| http://del.icio.us/rss/jacomien                       | http://del.icio.us/rss/jacomien                       | 
| http://del.icio.us/rss/tags/rmj20                     | http://del.icio.us/rss/tags/rmj20                     | 
| http://www.jihadwatch.org/index.rdf                   | http://www.jihadwatch.org/index.rdf                   | 
| http://www.connotea.org/rss/user/rmj20                | http://www.connotea.org/rss/user/rmj20                | 
| http://devblog.grazr.com/?feed=rss2x                  | http://devblog.grazr.com/?feed=rss2x                  | 
| http://feeds.feedburner.com/littlegreenfootballs/kyeH | http://feeds.feedburner.com/littlegreenfootballs/kyeH | 
+-------------------------------------------------------+-------------------------------------------------------+
7 rows in set (0.00 sec)