Safari on iPad does not have a Home button. You can save a page link icon on the Home Screen but that does not help when you are already in Safari. The answer is to create a link to your home page in the Safari Bookmarks Bar.
Begin by being sure the iPad's Bookmarks Bar is always visible by going to Settings » Safari » Always Show Bookmarks Bar and turning it on. Open Safari and navigate to your desired home page. Touch the + icon at the top of the window next to the search bar. Touch Add Bookmark. Give the page a short name such as Home, then touch the location button at the bottom of the dialog box if it does not say Bookmarks Bar. Select the Bookmarks Bar as the location, then touch Save.
Note for MobileMe users: This hint will place the link only on the iPad if you add the link through the iPad. If you add it to your desktop version of Safari, and have the iPad set to sync with MobileMe, the link will appear on all your Macs that sync with MobileMe bookmarks, including the iPad.
[crarko adds: I haven't tested this one.]
Mac OS X Hints