Creating a Bitcoin client that fully implements the network protocol is extremely difficult. Bitcoin-Qt is the only known safe implementation of a full node. Some other projects attempt to compete, but it is not recommended to use such software for anything serious. (Lightweight clients like Electrum and MultiBit are OK.)
You can download the Bitcoin bootstrap
torrent to speed up the process of syncing. The torrent will speed up the process, however it won't complete instantly.
Who wants bootstrap.dat?
Anyone bringing up a new node using the reference client. This is one method of accelerating the initial blockchain download process, while helping the bitcoin P2P network by offloading data download traffic from public P2P nodes.
This download is not for those who are already running the bitcoin client.