Unlike the SCSI driver (which can distinguish between CD-ROMs, tape drives and fixed disks), the address of most devices on the IDE bus (except tape drives) only depends on where it appears to be on the bus. Assuming you have an IDE controller, all you need to know to access it is what "hard drive position" it appears in:
Master on primary controller: hda
Slave on primary controller: hdb
Master on secondary controller/doubler: hdc
Slave on secondary controller/doubler: hdd
You can have more than two controllers: for example, hde and hdf correspond to the master and slave on the tertiary controller. You can currently have up to six IDE controllers on a system (and thus up to 12 drives).
This information should also appear in the boot messages. You can access up to 63 partitions on an IDE fixed disk. Note that the distinction between "primary" and "logical" partitions only applies to disks partitioned using the MS-DOS partitioning scheme.
Parallel IDE devices are currently not supported on any Linux/m68k system; however, the underlying hardware support is available on at least some Amiga IO cards.
Generally if you have just an IDE hard drive and an IDE CD-ROM, the CD-ROM will be hdb (depending on your master/slave settings).
Simply make a mount point (e.g. mkdir /cdrom) and then do mount -t iso9660 /dev/hd? /cdrom, replacing the ? with the drive letter from the list above.
IDE tape drives are accessed through /dev/hdt0 (/dev/nhdt0 for no-rewind-on-close). Note that only one IDE tape drive is supported.