I am using SQL Server 2008 express edition but I want to make my databases still in 2005. How can I set it up to only show features that a 2005 database can use?
Like for instance I don't remember there being a "date" type. I only remember "dateTime".
I don't want to be using features that 2005 can't support and I later on upload my db to the my hosting site that uses 2005 still and find out I am using things not supported by it.
You won't be able to upload the database, just a script of it. Even when in 90 compatibility mode, the physical structure of the database will be the 2008 one and the hosting site won't be able to load it.
Note that the compatibility level does not necessarily mean that the new features of SQL 2008 are not available, but instead it simply means that (some) features that existed in 2005 will work the same way in 2008. The complete list of compatibility mode changes is on MSDN. In particular there is nothing to prevent the usage of a datetime2, date, time or any new time in a database set at compatibility level 90. In fact such would be impossible simply because the the compatibility level can be changed after a table is created.
You are going to either develop against a SQL 2k5 instance, or read the product manual and learn what features are available in what version.