Please read this stickied topic about x10 hosting. Unfortunately, x10 hosting is no longer the best choice. If you poke around, you can find others, but I have no personal recommendations there (other than
99webs.org - but it's a one on one agreement with the owner, who does pop on our forums now and then, but Nemesis has to be online to approve you, so it could take a while).
If you're just interested in development and don't plan to get on paid hosting any time this century while you're still working out the kinks, might I suggest hosting it yourself... from your
very own computer? There are many Apache-MySQL-PHP packages that allow you to do just this -
I recently wrote a guide on a Windows one (WAMP), but if you have a different operating system it's still useful and I can probably help work out the details.