You can try Models! for Mac and iPad
Mac Version
-UML 2.0 Support
-Use-case diagrams
-Class and object diagrams
-Activity diagrams
-Component, deployment, package and composite structure diagrams
-Post-it notes, grids, alignment tools, coloring, formatting and search capabilities
-Integrated libraries of software architectures and patterns
-Class and Association Editing
-Code generation for Java, Objective-C and PHP
-Multi-touch zoom
-Export option to .PDF and .TIFF
-Customizable toolbar
-Useful enhancements: 1-click to copy&paste; resize proportionally...
iPad Version
-Class diagrams
-Use-case diagrams
-Entity-relationship diagrams
-Demo templates
-Snap grid option
-Shadows option
-Export to .pdf via email
A demo version is available on the project's
website
