I don`t know about such script , I know joomla had the option ( template chooser ) for the user. Maybe you can work something out with the help of that code...

Daniel, maybe you are looking for this plugin

i think Bagi's solution is the best way.visiters can choose the theme themselves.i think it is an example for that solution: Wordpress Themes you can choose the theme.

i do not use that way, i use folders like /demo1/, /demo2/, etc and install wordpress on each folder. i use the same dabase, just change the
"$table_prefix" in wp-config.php.by this change, you can use unlimited wordpress installations in one database.in these way, you should write the posts for every folder.if you do not change the "$table_prefix", installations will use the same database, so you do not need to write the posts for each wordpress in folders.

and, i could not try this solution because my server does not let me: you can use "wordpress mu".with wordpress mu, you can run unlimited blogs with a single wordpress installation.wordpress.org and blogger.com are using these kind of systems.after the wordpress mu installation, you can create new blogs and use different themes on each of your blogs.you can use subdomains or folders(theme1.domain.com or domain.com/theme1/).then you can show your themes.you can read more information about wordpress mu: WordPress MU › Home

if my english is not good, sorry about it

Erdem,
Thanks very much for this info, rep added, you are always a very helpful guy

thanks Temi.every member is very helpful in this forum.

Two brilliant solutions!
You have my respect guys!

I'm sorry that I couldn't give you much detailed info, but I have tendovaginitis

sorry to learen about that.

Originally Posted by Bagi Zoltán

tendovaginitis

That must have been caused by all the mischief you got up to when you girlfriend was away LOL . Hope it gets better soon .