esata related questions

Hello,

I have a few questions about esata that I hope you can help me with.
lets say I buy one of those new motherboards that have it built in,
so bracket containing : 2 esata ports, 1 power port. I could be mistaken tho..

1. Do I need an enclousure for an external hard drive? or can i simply get a cable to connect the esata and power port from the bracket to the hard drive? is it simply not recommended ?
2. I am interested to know how useable this interface is, can you install windows and boot from it? can you get speeds as a regular internal drive? (90mb/s avg speed)
3. If I buy a bracket (for an older PC), how would i install it? is it simply connecting the sata on the motherboard to the sata on the bracket? and how do i give it power? simple sata-connector-like power from the PSU?

I have toured the net, trying to ascertain the questions I have just asked you, they are all concerned with letting us know that there are 2 unidirectional cables for each side +3 grounds = 7 pins, and that there are 15 pins for the power... who gives a damn?

Thanks for your comment,
Could it be that some esata brackets do provide power?
I believe I saw a gigabyte motherboard (G33-DS3R) that includes an esata bracket that has a power port (at the back of the computer, allegedly to provide power for the esata device). I could be wrong though..