Okay - to do your hair in a regency style (has anyone else tried this btw? i often wear my hair like it).

if you want a parting you will need to do it in 2 parts. Depending how far back you want the parting take the front section of hair and tie it in a band to keep it out the way.
Take the back section and scrape it up into a high pony tail - you can put a band in if you want but it's not vital.
Twist your hair up and round into a tight bun and use hair pins to secure.
If you put a band in you can plait it before twisting into a bun and pinning.
Take the front section and make a parting so you have 2 sections of hair.
Take each one and join it to the bun using a pin, then wrap it round till it's just part of the bun. You can put each part bcak in a number of ways - either joining above or under the bun, or you could plait it perhaps? just try many things!
'Hair jewels' look quite nice and you can put a few in the back. You can get them from Monsoon (I have some nice pearl ones) but they're quite expensive there. Claires Accsessories maybe?
You could leave two or three sections hanging down and curl them with curling tongs - like Lizzy has (in bbc adaptation) - which looks quite nice.

This style looks more like Jane has it (you can add intricate plaits at the back but you'll probably need someone to do it for you.
A small mirror to check your hair from the back is v.useful!
That style only takes about 10 minutes (once you've got the hang of it)
To get it to look more like Emma has it (in Emma2), without a parting, just scrape your hair back into a high pony tail and secure with a small band (that can easily concealed - Tony and Guy's 'mini bungee cords' are quite good for this).
Take a small section of hair and wrap round the band to hide it, and secure with hair pins.If your hair is curly you can just kind of pin the curls up around your head, or if not pin up small sections at a time with a combination of hair pins/kirby grips.You could also add a ribbon (like in Emma2) round your bun, using hair pins.

If any parts of your hair are too short to put up you could leave them down and curl them, or just use a pretty or un-noticable kiby grip.

In short, it is best to find a picture of a style you like and just try and copy it. I just completly made all this up from watching p&p and Emma!
hope that helps!
Hafsa:)