situation where a person could use AE. it's a similar process but faster, and less intricate work, just make a mask of the text and tell it to slide along the course of the mask and wham bam thank you mam - it's a done deal. no intricate KF's all throughout the process.
I saw a tutorial once where you defined a gradient brush in Photoshop or Paint Shop Pro and you painted the letters with it and the gradient would follow the stroke from black to white. Then all you had to do was use it with a gradient dissolve and the letters would magically paint on the screen. I can't remember where I saw it and I don't know how to make a gradient brush in Photoshop but it is possible and doesn't take long to get good results.
If any of you have Ulead's (Now Corel's) PhotoImpact, you can easily do handwriting.
Create a new image, and apply the "Signature" effect in the animation studio. You can set a number of properties, keyframe it and save as an animated gif or sequential bmp. I've used a green backgound and brought the sequential files into Vegas and keyed the result over video. You can save the gif with transparent background and use that if you wish.
If this is a one shot deal, you could download the trial and do the animation. For me, PhotoImpact is worth every penny. It is a quite competent program.