http://www.vote-2007.co.uk/index.php?topic=771.75
Jonathan Arnott is/was the UKIP local elections coordinator, so his numbers should be reasonably accurate.
On the assumption that the 'ball park' number is just under 1000, is this good?
To put it in context, according to Iain Dale (who gave inaccurate UKIP numbers), the Tories have 9,264, Labour have 6,360, the Lib Dems have 6,667 and the BNP 717.
The Greens have 1,394 candidates.