Yes, On most controls attributes override the css, but I beleive that the LinkButton gives css priority. Set the CssStyle of the LinkButton to "SomeClass" then in the css copy/paste the 4 A:Link,A:Visited etc.... to a new section of the css file and change each of the 4 to this.... A.SomeClass:link, A.SomeClass:Visited, etc...
Of course once you have copied all four you can then change their colors and so on.