1. Open a new document in Illustrator
2. Using a very bold font, type your Postcard text
3. Select the type, and go to Type > Create Outlines
4. Go to Effect > Warp and adjust the "bend" of the text"
5. Go to Object > Ungroup
6. Go to Effect > 3D. Click and drag the image to have the correct 3D effect
7. Go to Object > Expand Appearance and the effects will appear
8. Select all objects and go to the color panel; select a random color. Then use the drop-down to specify RGB (or CMYK) color so it isn't in Greyscale
9. Ungroup all objects
10. Select all objects on top and make them white; Change the color of the 3D objects
11. Select the white letters and add a stroke using the color panel
12. Select the white letters and go to Object > Path > Offset Path. Set the Offset to a negative number to create "inner" layers. Set them to a different color.
13. Copy and paste onto an image in Photoshop.