An excerpt from http://www.sitepoint.com/building-custom-login-registration-pages-wordpress/, by Agbonghama Collins
WordPress started life as a blog engine, web software for creating blogs. Over the years, it has evolved into a content management system (CMS), even though some developers might disagree on it being considered a CMS.
There’s a healthy disrespect for the WordPress default login and registration pages, because they live outside the website without conforming to the site design.
When it comes to creating a website for clients, you might want a more customized login page, so that it integrates nicely with the website design as a whole. There are also numerous plugins that extend WordPress where the registration and login pages are used by end users, not just site administrators.
A couple of developers have released several kinds of plugins for customizing the default login and registration forms in WordPress such as the Custom Login Page Customizer.
The gripe about the default account page is not primarily because it isn’t pretty, but because it doesn’t have a connection to the website look and feel.
A quick Google search on building custom registration and login pages for WordPress reveals tutorials geared towards advanced PHP/WordPress developers. This is ok if you’re experienced, but as someone that’s written a lot of developer tutorials, I know there’s also an audience that needs something a bit simpler.
In this tutorial, we’ll learn how to build custom WordPress login, registration and password reset pages with a plugin I’ve developed called ProfilePress, all without writing a single line of PHP code. Of course, if you’re a developer, you’re welcome to check out the code too.