That's actually a pretty complicated question, but in general:
First, receiving the LLC membership interest in exchange for services should not be a tax issue in the US (assuming your services weren't performed in the US), but they may be taxable in your country of residence - so check there first.
Second, it matters whether the LLC is "engaged in a trade or business" in the US; that's a loaded term in itself, but assuming the answer is yes, you personally will be considered to be engaged in that trade or business through the LLC, and have to file annual US nonresident tax returns - the LLC will be required to provide you with something called Form K-1 every year to help you do that, but it's not a trivial matter.
Third, as mentioned in other answers, for various reason you may be subject to US tax on your share of LLC income even if you don't get cash distributions from the LLC - and vice versa, not be subject to US tax on cash distribution you did receive.
Finally, check again in your own country how LLCs are treated and taxed. In some places they're treated as corporations (companies) and in other as partnerships; the local tax consequences may be significantly different.
In short, don't jump head first into this opportunity before you check (with knowledgeable professionals) where this will leave you...