Although it is not possible to warp a text box, or have text flow along a shape or curve automatically, it is possible to have text follow a curve, or any shape manually.
Draw a circle or shape to use as a guide. Make a new text box, put one letter in it. Make sure the letter is exactly the style you want for the whole word. Resize the text box to fit the letter tightly. Click off the page then click the newly created text box to select it. Copy it, paste it. Move the newest box to about where it should be. Paste again, you will see that Pages will offset the next paste the same amount as what you did. Continue pasting until you have the same number of boxes, as letters in the word you need. Click each box and edit it for the letter that should be there. Use the circle or shape to help arrange the text boxes. Click on each text box and use the rotate circle in the 'metrics' tab (on the inspector) to align each text box with your guide. Delete the guide shape once done.
Note: depending on what else is around your text, you may wish to click the appropriate word wrap settings in the inspector's 'wrap' tab. Do this on the first text box before you start copy and pasting so that all the text boxes are correct.
Once done, click to select each box, and 'group' them. This way they can be moved, rotated and edited as a group. And this can be used to great effect! For example, by resizing the group using the resize object handles, you can squash down the text to make it look like it's lying flat in 3-D, or change the size of the arc. You can reuse this new 'word arc' in other projects to save you time.
I have found that once you really get to know Pages, you can get it to do most anything you want. Including things that it supposedly can't do. The real beauty of learning all the tricks of the inspector pre-trains you to use other iWork/iLife apps, as they share many of the same features.
Good luck!
