You just have to click and hold the link that has the mouseover effect. At first, you get a popup with the link or description. If you then release your finger, however, the mouseover effect is triggered!
一つのことを行い、またそれをうまくやるプログラムを書け -- Malcolm Douglas McIlroy
ないことはないけど… (スコア:1, 参考になる)
Trigger a mouseover event on the iPhone/iPod Touch - Mac OS X Hints [macosxhints.com]