You do have a fixed ip though m8 Could be someone has found a way in and they keep trying now?? Just being paranoid but it's entirely possible.
What router are you running? I have recently swapped to a wireless Netgear DG834. Locked down wireless using 128bit encryption, mac filtering all around the house. The router fully supports Upnp so MSN messenger can have sound and video and it also kindly emails you logs of scrotes port scanning.........
Sun, 2002-09-08 12:00:13 - LCP is allowed to come up.
Sun, 2002-09-08 12:00:16 - CHAP authentication success
Sun, 2002-09-08 12:04:38 - Send out NTP request to 195.10.105.250
Wed, 2004-12-01 23:05:32 - Receive NTP Reply from 195.10.105.250
Wed, 2004-12-01 23:00:54 - Router start up
Thu, 2004-12-02 04:03:43 - TCP Packet - Source:69.51.152.177,1699 Destination:193.82.xxx.x,135 - [DOS]
Thu, 2004-12-02 04:03:51 - TCP Packet - Source:69.51.152.177,1700 Destination:193.82.xxx.x,5900 - [DOS]
Thu, 2004-12-02 04:04:08 - TCP Packet - Source:69.51.152.177,1678 Destination:193.82.xxx.x,445 - [DOS]
Thu, 2004-12-02 04:04:16 - TCP Packet - Source:69.51.152.177,1696 Destination:193.82.xxx.x,1433 - [DOS]
Thu, 2004-12-02 04:04:25 - TCP Packet - Source:69.51.152.177,1699 Destination:193.82.xxx.x,135 - [DOS]
Thu, 2004-12-02 04:04:33 - TCP Packet - Source:69.51.152.177,1698 Destination:193.82.xxx.x,445 - [DOS]
Thu, 2004-12-02 04:04:41 - TCP Packet - Source:69.51.152.177,1700 Destination:193.82.xxx.x,5900 - [DOS]
59 quid from DABS and they rock erm dudes sweeeeeeeeeeet