Well spotted!
That's the race - it's an annual 10km race but last year (2005-2006) they've spiced it up a little by adding in some extra 5km races.
Normally Nike keep the date a big secret so it's quite surprising to see it advertised on RW already. There will also be a big advertising campaign when it gets launched and there's bound to be some "gimmick" attached - e.g. in 2004 the gimmick was that the race was run in the dark in November.
It will be a good, well organised race with a lot of people there - probably 30,000 to 40,000.
Not sure it's worth coming all the way from Wales for though - that's up to you I guess!