Question 1
Is there a difference between 'ialah' and 'adalah'?

Cikgu Yeoh answers:
If you are speaking of Standard Malay (Bahasa Baku), then the answer is 'yes'.
Both words belong to the group Kata Pemeri in Malay Grammar.
a) Kata pemeri 'ialah' is used before Frasa Nama (noun phrase) and Frasa
    Kerja (verbal phrase).
Examples:
1.1 Hashim ialah penyarah universiti itu.
(Hashim is a lecturer of that university.)
In the above sentence, 'pensyarah universiti itu' is the noun phrase.

1.2 Tujuan projek ini ialah untuk membantu golongan miskin.
(The aim of this project is to help the poor.)
The verbal phrase in this sentence is 'untuk membantu golongan miskin'.
(Note that 'untuk' here is considered a conjuction)

1.3 Baju ini adalah terlalu mahal.
(This shirt is too expensive.)
The words after 'adalah', i.e. 'terlalu mahal' is an adjectival phrase.

1.4 Hadiah ini adalah untuk adik saudara.
(This gift is for your younger brother/younger sister)
The part that forms the prepositional phrase in the above sentence is 'untuk adik saudara'. (Note that 'untuk' can exist as 'conjunction' and 'prepostion' and in this case, it is a preposition).

Question 2

"How to tell whether a verb is  a Kata Kerja Transitif or a Kata Kerja Tak Transitif?"

Cikgu Yeoh Answers:
Well, some explanation is needed before I start. There are certain things which you must know about both of them. They will be explained later in this home page under Parts of Speech which has not been completed yet. Anyway, let me tell you how to differentiate between the two quickly. Take a verb, for example  berjalan and asks two questions after it, i.e.
"berjalan apa" (walk what)? or "berjalan siapa" (walk who)? If there is an answer to either of the two questions, then the verb is a Kata Kerja Transitif (Transitive Verb). Otherwise, it is not. In this case 'berjalan' is not a Kata Kerja Transitif, so it must be 'Kata Kerja Tak Transitif'.

Now, look at another verb, for example 'menemui' (to meet). Ask the two questions namely 'menemui apa' or 'menemui siapa'. The first question has no answer whereas the second questions has an answer. So the verb 'menemui' is a Kata Kerja Transitif.

Another distinction is that a Kata Kerja Transitif has prefix meN (me , mem, men, meng, meny or menge) before it. Examples of them are
menemani, menajamkan, menonton, memanggil, membasmi, mengumpulkan and merancang.