The download time should (with the latest released version) be on par with the time it takes to download the Bitcoin blockchain. As mentioned in another reply, the best way to get started quickly is downloading the torrent provided:
http://bitcredit-currency.org/viewtopic.php?f=18&t=517

Once that is done, make sure the client is in sync:
http://bitcredit-currency.org/viewtopic.php?f=18&t=17

Once that is done, enable the miner with:
"setgenerate true 2"
See this description for further details:
http://bitcredit-currency.org/viewtopic.php?f=18&t=18