Both registration and login pages are critical pieces of any interactive web site. A couple of posts popped up last week that provide good tips for each.
The critical thing to keep in mind with pages like these is to pare them down to just the bare essentials of what is needed to get the user where they want to be. This can be really tough to do at times, organizations being what they are, but you will be rewarded for your efforts if you can hold the line.
An interesting caveat to the above: do not ignore the marketing opportunities that a login page for restricted content provides. You can show the value of what is behind the login and offer a next step to do what they need to do to gain access (which probably involves giving you money). You still have to make sure those messages don’t get in the way of those who already have access while being visible enough to attract the attention of those who are your potential customers/members.