First go into your photos, and get to the point where you are looking at all your thumbnails. Now near the bottom you'll see the icon that you use to email with; Click on that and you will be able to select multiple pictures.
Select your pics, click share and then choose email or MMS.
*note you can only "share" 5 pics at a time.. but you can copy and paste more!
Yep definitely one of the most overlooked, best new features of 3.0!
"In the photo album, tap the arrow icon in the lower-left corner of the screen. Then tap the photos you want to e-mail. Tap the Share button, then E-mail. The mail application will open with your photos embedded in a composition window."