UI element libraries can be really helpful - especially when the deadline is TIGHT. The good folks over at Web Design Ledger have gathered a great collection of 12 free PSD UI libraries - take a look and see what you think - they're free, did we mention that? >>
Nothing better than free stuff -- in this case it's a totally free full user interface design kit from Pixelkit.com for registered CoolHomepages users -- take a look >>
Free Photoshop files to make your life a little easier: Some pretty nice web UI elements from our friends at DesignModo. You will have to tweet about it to get the download, so there, I warned you. But hey, that's fair enough.. tweets are free and somebody had to take the time to do this. They should help you out and we hope you will enjoy them too! PSD Web UI Set is fully layered, web elements have hover and normal states. Colors of buttons can easily be changed according to user taste and needs.