I generally despise having to install Oracle software because it's so big and bloated, it's scary. Most downloads won't fit on a typical CD, even their Oracle Express edition is bigger than Microsoft Windows! I don't know what Express means to them, but "huge" isn't the description I would think of.
But there is light at the end of the tunnel, Oracle now has Instant Client which is only 35MB! Wow! And all you have to do is unzip it. It includes OCI, OCCI, and JDBC drivers, but if you want to make it useful out of the box, you should get the SQL Plus package for Instant Client (722KB!) and unzip it into the same directory. Put your tnsnames.ora into the directory as well if required. Then run sqlplus.exe as you normally would and voila, you're done.
- Download Oracle Instant Client
- Download SQL*Plus for Instant Client (from same download page)
- Unzip Instant Client into a directory
- eg: c:\oracle_ic
- Unzip SQL*Plus into the same directory
- Put tnsnames.ora into the same directory (OPTIONAL)
- Run: sqlplus username/password@SID
Get SQL Explorer for a free JDBC based client if you want to connect with a visual client.