Is there a way I can insert HTML on multiple sites, kindof like .css but html?

maybe this will be the one you where looking for:

http://www.lissaexplains.com/html6.shtml#SSI

Love,
Mirna

Oh yeah! x_x; I forgot about that, but is there any other way without having to put the .shtml extension on? Thanks.

Well yeah PHP, but then your host must allow PHP (most domains do so if you are hosted then could use this) but then again your pages will have to change to index.php etc

Love,
mirna

Allrighty. Thanks :)