Don't you hate that? But actually LJ does have a spellchecker. To the right of "post comment" and "more options" it has a box you can check that says "check spelling and preview" (not that I ever do...)
If you aren't seeing it maybe you can adjust some settings on you LJ friends page?
Re: make NOTE to self...
If you aren't seeing it maybe you can adjust some settings on you LJ friends page?