The learning curve for someone of your credentials should be, IMHO, fairly short. Java is Java, after all. Its just working with some new APIs and learning to make do without
alot of things, like floating point math, etc. Actual deployment, however, IMHO, can be a fairly complicated procedure. However, welcome aboard, and good luck! Once again, IMHO, I believe J2ME to be the real strength and future of Java, from cell phone apps to those pesky 'thin clients' Sun is always talking about....