this question is a little non specific but search engines will read index.php as your homepage just fine.
PHP is overtaking ASP [webmasterworld.com]
Yes there are lots of ways to call php to write content into an html page. I hate to keep harping on this but php.net has all of these answers.
Scorpion, I do not mean any offense but the last bunch of posts have been fairly similar in their questions. I myself have answered a few. If you just go to the above mentioned site you can have these answers more quickly and more concisely than if you keep asking us. The documentation on that site is phenomenal. They don't go into search engine questions, granted, but as far as language basics go there is no better resource available.
Just trying to be helpful, I don't want to discourage you from posting just that if you spend a little time on that site you can stop needing our help for the basic stuff and throw some more hardcore questions.
As Brett mentioned in a post not long ago we try to help people learn as opposed to handing them answers on a silver platter. I am glad you are getting into php and it looks you will soon be stretching its limits quite a bit very soon. I am interested to see what you come up with as things progress.
hope this helps a little.