ipads/ipod touches can be great.
the main advantages for dd1 have been:
ease of use (she did not 'get' the mouse/cursor correlation for a long time)
immersive quality
apps are cheap, so I can download a few variations for her to try out, without worrying greatly if she doesn't take ot it - much easier to 'waste' 79p than £5+ on a board game/flashcards/whatever
we have loads of apps for dd1 (dd2 uses them too). list far too long to re-type, but if you use the search, and search for my posts (in all topics) on apps, then a few threads should come up which are useful.
off the top of my head, particular favourites for us have been:
Grasshopper apps - great apps for spelling/reading which are fully customisable. also a telling the time app which dd1 has loved.
Open University Our Story app. fantastic if your dc likes storybooks - you make your own by using your own photos, and can customise each page with appropriate words/phrases, and record the sentence/phrase too.
iwritewords: great for learning to trace/write letters and spell too.
kindergarten apps (I think) do a good range of ABA style apps - lots of Feature Function Class style mini games.
Teachme range (teachmetoddler, teachme 1st grade etc)
pocketphonics is ace.
montessori words and numbers apps are good for initial numberbonds/counting and letter recognition.
they are my favourite educational ones, probably. but there are so many more. lots of counting/maths games, even games like classic pelmanism can really help with improving memory and recognition. apps like I see ewe, shapebuilder, preschool adventure,old macdonalds farm,animal farm, iplay and sing, have all helped dd1 along the way too.
dd1 has her own ipad, fundraised for at ehr last school. without it, she would not now be reading and writing (she probably would have got there eventually, but certainly not so soon - she is 7, and can spell simple words, write almost legibly, and read simple stories. this has all happened since she got her ipad, through the use of apps such as little speller and our story)