You can set TextMode for textbox to Multiline, this will align the text inside textbox to top.
For other type of styling you should think CSS, and what elements are actually rendered, look at the page source in browser during debugging. For example Gridviews produce Html Table elements with TR rows and TD cells, and Asp.net Textbox produce a Html Input (text) element, while Asp.net Textbox with Textmode=Multiline produces a Html Textarea element. So basically you are looking as CSS solutions for either a 'input text' or textarea inside a TD.