but boggled about how to do this

I'd like to take make an alias for the IC channel

ic *

Thats easy, I'd like to take the wildcard and replace any vowels with a particular letter.

if i Ic something, it'd replace all the vowels with a letter i choose.

I.E. you ic 'You know I think your right'

becomes:
you ic 'UUU knuw U thunk uuur rught'

Or something to that affect.

I'm not too sure where to start, I know I'll probably have to use the split command, and case to replace the letters, Thats not the hard part, its re-forming the sentence and what not.

If this isn't even possible lemme know.

I can't write the actual code now, but what I will tell you it should be easy. This is only pseudocode

Dim vowels = "aeiou"
Dim intcounter

For intcounter = 1 to len(strword)
if instr(vowels, mid(strword, intcounter, 1)) > 0 then
strstring = strstring & "<the letter you want"
else
strstring = strstring & mid(strword, intcounter, 1)
end if
next

It basically looks at the letters one by one. If a letter is a vowel, it copies another letter in the string. If not, it copies the actual letter.
I don't remember how mid and instr work offhand, you should look them up.

If you want to replace all vowels with the same letter you could use the replace script function, eg.

str = world.Replace ("str", "a", "u", vbTrue)
str = world.Replace ("str", "e", "u", vbTrue)
str = world.Replace ("str", "i", "u", vbTrue)
str = world.Replace ("str", "o", "u", vbTrue)

This is a bit inefficient, as you are doing it 4 times (you won't need to replace U by itself) however it might not be much slower than doing it in a loop.

My example doesn't preserve capitalisation, you might need another 4 lines for the upper-case letters.