input foo, output '[F|f][O|o][O|o]'?

["TJ Luoma" <luomat@xxxxxxxxx>]

Before I reinvent the wheel, I thought I'd ask if someone already had 
(or knew of) a way to take a string of characters and output a 'case 
insensitive' regex version.

For example, if I input 'CrashPlan' I'd want to get out 
[C|c][R|r][A|a][S|s][H|h][P|p][L|l][A|a][N|n]

(Input will usually be ASCII letters, with an occasional number and 
perhaps the occasional '-' or '_' but doesn't need to handle anything 
more complex than that.)

I tried Google but found it pretty impossible to make a good query for 
something like this.

TjL