Just got notice that pair.com is upgrading all their servers to PHP 5.3.5. in the next few weeks.

Anyone else anticipating problems?

See http://drupal.org/requirements.

PHP 5.3 is not yet supported by Drupal 5.x, but is supported by Drupal 6.14 core and higher (see the release notes for 6.14) and recommended fr Drupal 7.x. Note that some contributed modules may not be compatible with PHP 5.3, and that some PHP 5.3 configurations still show warnings with Drupal 6.14; work is ongoing to resolve the latter in #360605: PHP 5.3 Compatibility.

I've been advised by their support team to use php-cgiwrap to run Drupal through 5.2. Perhaps that will work.