Completed listings in eBay will give you some data (15 days), that you need to wade through.
But Mpire gives you 30 days, and the data is already analysed. And it's free :-)
Info includes listing duration, best time to end, best day to end, best keywords, etc.
Go to www.mpire.com, scroll down and cick on Researcher. Register there for a free account.
The data only applies to eBay US, but still gives a good indication, I think, for other countries.