The tilde shorthand notation is built-in to bash, so you can't really create equivalents to that, but you can use aliases, like this:
This only works for executable files, as far as I know. For normal files, though, you might just create a symbolic link to the file you want to use, like this:
ln -s /mnt/hda2/txt/phone.txt ~/ph
That'll create a file called 'ph' in your home directory that links directly to /mnt/hda2/txt/phone.txt. Then you can do things like 'grep Melissa ~/ph'.