The aliasing on text will vary depending on:
Operating system (Windows 7, Windows XP, Mac OSX, Ubuntu etc etc etc)
Web browser (Internet Explorer 8, Firefox, Google Chrome, Safari etc etc etc)
User specific settings in both the web browser and operating system.
When you do mock-ups in Photoshop it is best to either ignore the smooth text or use "none" in the alias option, but you will not be able to accurately replicate how the text will display either way.
2) Photoshop uses a different font renderer than browsers do... every OS uses a different font renderer... you cannot guarantee even the same fonts are available across systems...
So as others are saying, the mere NOTION of fonts appearing identical to what is in your PSD is basically a failure to understand what the Internet is and how to develop for it... Though that usually goes hand in hand with drawing some goofy picture in photoshop and then thinking it has anything to do with building a proper website; a flawed strategy at best as it usually results in shoe-horning content into a layout it was never meant for.