Student Visas - how easy or how complicated

We're moving to KL around July of this year.  We are looking around for suitable international schools for my 2 kids (primary and secondary).  My question is how simple or how complicated is it to secure student visas for the kids?  How long does the process take?

Thanks!

Kids can get a student pass if they attend Grade 1 and above (i.e. from 6-7 years). Otherwise they would be on a dependent pass (so would the spouse) that is sponsored through the employment pass (or MM2H) of one of the parents. The selected school provides some paperwork to confirm admittance and then usually the employer will submit this together with the appropriate application forms to obtain the passes. There are examples of the forms required here -   expats.com.my/expats2009/expat_dl.html