If you don't want to have to change it based on the name of the submit button this has worked for me. I found it somewhere so I don't take credit for writing it.
Code:
For j = 0 To WebBrowser1.Document.Forms(0).length - 1
If WebBrowser1.Document.Forms(0)(j).Type = "submit" Then
WebBrowser1.Document.Forms(0)(j).Click
Accounts = Accounts + 1
End If
Next j