Posts Previews in Index, Archive & Search Pages?

Hi!

I upgraded my blog to the 2.2.2 version & “post teaser” plugin wasn’t compatible.

I noticed in my theme, that unlike index & archive pages, search pages show previews of posts instead of full posts, so I opened the search.php & index.php & found this differences:

search.php
<?php the_excerpt() ?>
index.php
<?php the_content('Read the rest of this entry &raquo;'); ?>

I replaced the 2nd code with the 1st in index.php & archive.php & I’m very happy with the result ??

I just want to know if I can add some advanced features (I’m a total noob in php btw)

1. can add some code to choose the length of the preview? 10 or 20 words for example?

2. I added a line to warn readers that what they see is a preview not the full post:

This is a preview, click on the title above to see the full post.

Can I instead make it like this:

This is a preview, click here to see the full post.

& have the link to the post there?

Thanks in advance! I also hope this will help people who have troubles with “post teaser” to get a definitive solution. ??