I'd like to add some code to the top of the right side bar. Where do I do this and in what file?

Thanks

For HTML and Javascript code use the text widget, for PHP code this widget http://wordpress.org/extend/plugins/php-code-widget/

thanks for that - I was trying the text widget but php would not go in. I'll install that plugin

I installed the plugin and put in this:
<?php include 'http://www.mydomain.de/wordpress/link.php'; ?>

and get this error

Warning: include() [function.include]: URL file-access is disabled in the server configuration in /var/www/web58/html/nydomain/wp-content/plugins/php-code-widget/execphp.php(37) : eval()'d code on line 1

what`s wrong???

Try to add this to your .htaccess file

php_value allow_url_fopen on

or create a .htaccess file with that content

But if you're using permalinks you should have a .htaccess file at /yourdomain.com/.htaccess

Or perhaps your host allows a custom php.ini. Then put

allow_url_fopen On

into your custom php.ini

Or use curl http://www.php.net/manual/en/curl.examples-basic.php
That may be allowed on your host

It's not working. Do you have another idea? It's a problem with my provider/webspace?